MySQL/MariaDB数据库的存储过程
MySQL/MariaDB数据库的存储过程
作者：尹正杰
版权声明：原创作品，谢绝转载！否则将追究法律责任。
一.存储过程概述
1>.存储过程优势
存储过程把经常使用的SQL语句或业务逻辑封装起来,预编译保存在数据库中,当需要时从数据库中直接调用,省去了编译的过程
提高了运行速度
同时降低网络数据传输量
2>.存储过程与自定义函数的区别
存储过程实现的过程要复杂一些,而函数的针对性较强
存储过程可以有多个返回值,而自定义函数只有一个返回值
存储过程一般独立的来执行,而函数往往是作为其他SQL语句的一部分来使用
3>.存储过程存储位置
存储过程保存在mysql.proc表中。
MariaDB [yinzhengjie]> SELECT * FROM mysql.proc\G #不难发现存储过程和函数都保存在该表中。 *************************** 1. row *************************** db: mysql name: AddGeometryColumn type: PROCEDURE specific_name: AddGeometryColumn language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: DEFINER param_list: catalog varchar(64), t_schema varchar(64), t_name varchar(64), geometry_column varchar(64), t_srid int returns: body: begin set @qwe= concat('ALTER TABLE ', t_schema, '.', t_name, ' ADD ', geometry_column,' GEOMETRY REF_SYSTEM_ID=', t_srid); PREPARE ls from @qwe; exe cute ls; deallocate prepare ls; end definer: root@localhost created: 2019-10-26 22:17:15 modified: 2019-10-26 22:17:15 sql_mode: comment: character_set_client: utf8 collation_connection: utf8_general_ci db_collation: latin1_swedish_ci body_utf8: begin set @qwe= concat('ALTER TABLE ', t_schema, '.', t_name, ' ADD ', geometry_column,' GEOMETRY REF_SYSTEM_ID=', t_srid); PREPARE ls from @qwe; exe cute ls; deallocate prepare ls; end*************************** 2. row *************************** db: mysql name: DropGeometryColumn type: PROCEDURE specific_name: DropGeometryColumn language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: DEFINER param_list: catalog varchar(64), t_schema varchar(64), t_name varchar(64), geometry_column varchar(64) returns: body: begin set @qwe= concat('ALTER TABLE ', t_schema, '.', t_name, ' DROP ', geometry_column); PREPARE ls from @qwe; execute ls; deallocate prepare ls; en d definer: root@localhost created: 2019-10-26 22:17:15 modified: 2019-10-26 22:17:15 sql_mode: comment: character_set_client: utf8 collation_connection: utf8_general_ci db_collation: latin1_swedish_ci body_utf8: begin set @qwe= concat('ALTER TABLE ', t_schema, '.', t_name, ' DROP ', geometry_column); PREPARE ls from @qwe; execute ls; deallocate prepare ls; en d*************************** 3. row *************************** db: yinzhengjie name: students_numbers type: FUNCTION specific_name: students_numbers language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: DEFINER param_list: returns: smallint(6) body: BEGIN DECLARE x SMALLINT; SELECT COUNT(StuID) FROM students INTO x; RETURN x; END definer: root@localhost created: 2019-10-28 20:38:19 modified: 2019-10-28 20:38:19 sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci db_collation: utf8_general_ci body_utf8: BEGIN DECLARE x SMALLINT; SELECT COUNT(StuID) FROM students INTO x; RETURN x; END *************************** 4. row *************************** db: yinzhengjie name: deleteById type: FUNCTION specific_name: deleteById language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: DEFINER param_list: uid SMALLINT UNSIGNED returns: varchar(100) CHARSET utf8 body: BEGIN DELETE FROM students WHERE stuid = uid; RETURN (SELECT COUNT(stuid) FROM students); END definer: root@localhost created: 2019-10-28 20:06:27 modified: 2019-10-28 20:06:27 sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci db_collation: utf8_general_ci body_utf8: BEGIN DELETE FROM students WHERE stuid = uid; RETURN (SELECT COUNT(stuid) FROM students); END *************************** 5. row *************************** db: yinzhengjie name: addTwoNumber type: FUNCTION specific_name: addTwoNumber language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: DEFINER param_list: x SMALLINT UNSIGNED, Y SMALLINT UNSIGNED returns: smallint(6) body: BEGIN DECLARE a, b SMALLINT UNSIGNED; SET a = x, b = y; RETURN a+b; END definer: root@localhost created: 2019-10-28 20:13:59 modified: 2019-10-28 20:13:59 sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci db_collation: utf8_general_ci body_utf8: BEGIN DECLARE a, b SMALLINT UNSIGNED; SET a = x, b = y; RETURN a+b; END *************************** 6. row *************************** db: yinzhengjie name: showTime type: PROCEDURE specific_name: showTime language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: DEFINER param_list: returns: body: BEGIN SELECT now(); END definer: root@localhost created: 2019-10-28 20:49:09 modified: 2019-10-28 20:49:09 sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci db_collation: utf8_general_ci body_utf8: BEGIN SELECT now(); END *************************** 7. row *************************** db: yinzhengjie name: dorepeat type: PROCEDURE specific_name: dorepeat language: SQL sql_data_access: CONTAINS_SQL is_deterministic: NO security_type: DEFINER param_list: n INT returns: body: BEGIN SET @i = 0; SET @sum = 0; REPEAT SET @sum = @sum+@i; SET @i = @i + 1; UNTIL @i > n END REPEAT; END definer: root@localhost created: 2019-10-28 21:32:01 modified: 2019-10-28 21:32:01 sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci db_collation: utf8_general_ci body_utf8: BEGIN SET @i = 0; SET @sum = 0; REPEAT SET @sum = @sum+@i; SET @i = @i + 1; UNTIL @i > n END REPEAT; END 7 rows in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
二.存储过程实战
MariaDB [yinzhengjie]> HELP CREATE PROCEDURE; Name: 'CREATE PROCEDURE' Description: Syntax: CREATE [DEFINER = { user | CURRENT_USER }] PROCEDURE sp_name ([proc_parameter[,...]]) [characteristic ...] routine_body CREATE [DEFINER = { user | CURRENT_USER }] FUNCTION sp_name ([func_parameter[,...]]) RETURNS type [characteristic ...] routine_body proc_parameter: [ IN | OUT | INOUT ] param_name type func_parameter: param_name type type: Any valid MySQL data type characteristic: COMMENT 'string' | LANGUAGE SQL | [NOT] DETERMINISTIC | { CONTAINS SQL | NO SQL | READS SQL DATA | MODIFIES SQL DATA } | SQL SECURITY { DEFINER | INVOKER } routine_body: Valid SQL routine statement These statements create stored routines. By default, a routine is associated with the default database. To associate the routine explicitly with a given database, specify the name as db_name.sp_name when you create it. The CREATE FUNCTION statement is also used in MySQL to support UDFs (user-defined functions). See https://mariadb.com/kb/en/create-function-udf/. A UDF can be regarded as an external stored function. Stored functions share their namespace with UDFs. See http://dev.mysql.com/doc/refman/5.5/en/function-resolution.html, for the rules describing how the server interprets references to different kinds of functions. To invoke a stored procedure, use the CALL statement (see [HELP CALL]). To invoke a stored function, refer to it in an expression. The function returns a value during expression evaluation. CREATE PROCEDURE and CREATE FUNCTION require the CREATE ROUTINE privilege. They might also require the SUPER privilege, depending on the DEFINER value, as described later in this section. If binary logging is enabled, CREATE FUNCTION might require the SUPER privilege, as described in https://mariadb.com/kb/en/binary-logging-of-stored-routines/. By default, MySQL automatically grants the ALTER ROUTINE and EXECUTE privileges to the routine creator. This behavior can be changed by disabling the automatic_sp_privileges system variable. See https://mariadb.com/kb/en/stored-routine-privileges/. The DEFINER and SQL SECURITY clauses specify the security context to be used when checking access privileges at routine execution time, as described later in this section. If the routine name is the same as the name of a built-in SQL function, a syntax error occurs unless you use a space between the name and the following parenthesis when defining the routine or invoking it later. For this reason, avoid using the names of existing SQL functions for your own stored routines. The IGNORE_SPACE SQL mode applies to built-in functions, not to stored routines. It is always permissible to have spaces after a stored routine name, regardless of whether IGNORE_SPACE is enabled. The parameter list enclosed within parentheses must always be present. If there are no parameters, an empty parameter list of () should be used. Parameter names are not case sensitive. Each parameter is an IN parameter by default. To specify otherwise for a parameter, use the keyword OUT or INOUT before the parameter name. *Note*: Specifying a parameter as IN, OUT, or INOUT is valid only for a PROCEDURE. For a FUNCTION, parameters are always regarded as IN parameters. An IN parameter passes a value into a procedure. The procedure might modify the value, but the modification is not visible to the caller when the procedure returns. An OUT parameter passes a value from the procedure back to the caller. Its initial value is NULL within the procedure, and its value is visible to the caller when the procedure returns. An INOUT parameter is initialized by the caller, can be modified by the procedure, and any change made by the procedure is visible to the caller when the procedure returns. For each OUT or INOUT parameter, pass a user-defined variable in the CALL statement that invokes the procedure so that you can obtain its value when the procedure returns. If you are calling the procedure from within another stored procedure or function, you can also pass a routine parameter or local routine variable as an IN or INOUT parameter. The following example shows a simple stored procedure that uses an OUT parameter: MariaDB> delimiter // MariaDB> CREATE PROCEDURE simpleproc (OUT param1 INT) -> BEGIN -> SELECT COUNT(*) INTO param1 FROM t; -> END// Query OK, 0 rows affected (0.00 sec) MariaDB> delimiter ; MariaDB> CALL simpleproc(@a); Query OK, 0 rows affected (0.00 sec) MariaDB> SELECT @a; +------+ | @a | +------+ | 3 | +------+ 1 row in set (0.00 sec) The example uses the mysql client delimiter command to change the statement delimiter from ; to // while the procedure is being defined. This enables the ; delimiter used in the procedure body to be passed through to the server rather than being interpreted by mysql itself. See https://mariadb.com/kb/en/stored-procedure-overview/. The RETURNS clause may be specified only for a FUNCTION, for which it is mandatory. It indicates the return type of the function, and the function body must contain a RETURN value statement. If the RETURN statement returns a value of a different type, the value is coerced to the proper type. For example, if a function specifies an ENUM or SET value in the RETURNS clause, but the RETURN statement returns an integer, the value returned from the function is the string for the corresponding ENUM member of set of SET members. The following example function takes a parameter, performs an operation using an SQL function, and returns the result. In this case, it is unnecessary to use delimiter because the function definition contains no internal ; statement delimiters: MariaDB> CREATE FUNCTION hello (s CHAR(20)) MariaDB> RETURNS CHAR(50) DETERMINISTIC -> RETURN CONCAT('Hello, ',s,'!'); Query OK, 0 rows affected (0.00 sec) MariaDB> SELECT hello('world'); +----------------+ | hello('world') | +----------------+ | Hello, world! | +----------------+ 1 row in set (0.00 sec) Parameter types and function return types can be declared to use any valid data type, except that the COLLATE attribute cannot be used prior to MySQL 5.5.3. As of 5.5.3, COLLATE can be used if preceded by the CHARACTER SET attribute. The routine_body consists of a valid SQL routine statement. This can be a simple statement such as SELECT or INSERT, or a compound statement written using BEGIN and END. Compound statements can contain declarations, loops, and other control structure statements. The syntax for these statements is described in https://mariadb.com/kb/programmatic-and-compound-statements. MySQL permits routines to contain DDL statements, such as CREATE and DROP. MySQL also permits stored procedures (but not stored functions) to contain SQL transaction statements such as COMMIT. Stored functions may not contain statements that perform explicit or implicit commit or rollback. Support for these statements is not required by the SQL standard, which states that each DBMS vendor may decide whether to permit them. Statements that return a result set can be used within a stored procedure but not within a stored function. This prohibition includes SELECT statements that do not have an INTO var_list clause and other statements such as SHOW, EXPLAIN, and CHECK TABLE. For statements that can be determined at function definition time to return a result set, a Not allowed to return a result set from a function error occurs (ER_SP_NO_RETSET). For statements that can be determined only at runtime to return a result set, a PROCEDURE %s can't return a result set in the given context error occurs (ER_SP_BADSELECT). USE statements within stored routines are not permitted. When a routine is invoked, an implicit USE db_name is performed (and undone when the routine terminates). The causes the routine to have the given default database while it executes. References to objects in databases other than the routine default database should be qualified with the appropriate database name. For additional information about statements that are not permitted in stored routines, see https://mariadb.com/kb/en/stored-routine-privileges/ . For information about invoking stored procedures from within programs written in a language that has a MySQL interface, see [HELP CALL]. MySQL stores the sql_mode system variable setting that is in effect at the time a routine is created, and always executes the routine with this setting in force, regardless of the server SQL mode in effect when the routine is invoked. The switch from the SQL mode of the invoker to that of the routine occurs after evaluation of arguments and assignment of the resulting values to routine parameters. If you define a routine in strict SQL mode but invoke it in nonstrict mode, assignment of arguments to routine parameters does not take place in strict mode. If you require that expressions passed to a routine be assigned in strict SQL mode, you should invoke the routine with strict mode in effect. URL: https://mariadb.com/kb/en/create-procedure/ MariaDB [yinzhengjie]>
1>.创建存储过程
MariaDB [yinzhengjie]> DELIMITER // MariaDB [yinzhengjie]> CREATE PROCEDURE showTime() -> BEGIN -> SELECT now(); -> END// Query OK, 0 rows affected (0.01 sec) MariaDB [yinzhengjie]> DELIMITER ; MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> DELIMITER // MariaDB [yinzhengjie]> CREATE PROCEDURE selectById(IN uid SMALLINT UNSIGNED) #需要用户传入一个参数，然后根据用户传入的参数做相应的处理 -> BEGIN -> SELECT * FROM students WHERE stuid = uid; #根据用户输入的参数查询相应的stuid。 -> END// Query OK, 0 rows affected (0.01 sec) MariaDB [yinzhengjie]> DELIMITER ; MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> DELIMITER // MariaDB [yinzhengjie]> CREATE PROCEDURE dorepeat(n INT) -> BEGIN -> SET @i = 0; #注意此处定义的是会话变量，尽管调用存储过程结束，改变了依旧可以在调用的会话中查询到。 -> SET @sum = 0; -> REPEAT SET @sum = @sum+@i; SET @i = @i + 1; #循环体为重复对sum执行累加操作，步长为1. -> UNTIL @i > n END REPEAT; #结束循环条件是会话变量"i"的值大于用户传入的参数 -> END// Query OK, 0 rows affected (0.01 sec) MariaDB [yinzhengjie]> DELIMITER ; MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> DELIMITER // MariaDB [yinzhengjie]> CREATE PROCEDURE deleteById(IN uid SMALLINT UNSIGNED, OUT num SMALLINT UNSIGNED) -> BEGIN -> DELETE FROM students WHERE stuid >= uid; -> SELECT row_count() into num; #将更新的行数保存到num变量中，改变了会随着存储过程调用而传出。 -> END// Query OK, 0 rows affected (0.00 sec) MariaDB [yinzhengjie]> DELIMITER ; MariaDB [yinzhengjie]> 说明: 创建存储过程deleteById,包含一个IN参数和一个OUT参数.调用时,传入删除的ID和保存被修改的行数值的用户变量@Line,select @Line;输出被影响行数
2>.查看存储过程列表
MariaDB [yinzhengjie]> SHOW PROCEDURE STATUS; +-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+| Db | Name | Type | Definer | Modified | Created | Security_type | Comment | character _set_client | collation_connection | Database Collation |+-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+| mysql | AddGeometryColumn | PROCEDURE | root@localhost | 2019-10-26 22:17:15 | 2019-10-26 22:17:15 | DEFINER | | utf8 | utf8_general_ci | latin1_swedish_ci || mysql | DropGeometryColumn | PROCEDURE | root@localhost | 2019-10-26 22:17:15 | 2019-10-26 22:17:15 | DEFINER | | utf8 | utf8_general_ci | latin1_swedish_ci || yinzhengjie | deleteById | PROCEDURE | root@localhost | 2019-10-28 21:23:31 | 2019-10-28 21:23:31 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci || yinzhengjie | dorepeat | PROCEDURE | root@localhost | 2019-10-28 21:32:01 | 2019-10-28 21:32:01 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci || yinzhengjie | selectById | PROCEDURE | root@localhost | 2019-10-28 21:21:37 | 2019-10-28 21:21:37 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci || yinzhengjie | showTime | PROCEDURE | root@localhost | 2019-10-28 20:49:09 | 2019-10-28 20:49:09 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci |+-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+6 rows in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> SHOW PROCEDURE STATUS\G *************************** 1. row *************************** Db: mysql Name: AddGeometryColumn Type: PROCEDURE Definer: root@localhost Modified: 2019-10-26 22:17:15 Created: 2019-10-26 22:17:15 Security_type: DEFINER Comment: character_set_client: utf8 collation_connection: utf8_general_ci Database Collation: latin1_swedish_ci *************************** 2. row *************************** Db: mysql Name: DropGeometryColumn Type: PROCEDURE Definer: root@localhost Modified: 2019-10-26 22:17:15 Created: 2019-10-26 22:17:15 Security_type: DEFINER Comment: character_set_client: utf8 collation_connection: utf8_general_ci Database Collation: latin1_swedish_ci *************************** 3. row *************************** Db: yinzhengjie Name: deleteById Type: PROCEDURE Definer: root@localhost Modified: 2019-10-28 21:23:31 Created: 2019-10-28 21:23:31 Security_type: DEFINER Comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci Database Collation: utf8_general_ci *************************** 4. row *************************** Db: yinzhengjie Name: dorepeat Type: PROCEDURE Definer: root@localhost Modified: 2019-10-28 21:32:01 Created: 2019-10-28 21:32:01 Security_type: DEFINER Comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci Database Collation: utf8_general_ci *************************** 5. row *************************** Db: yinzhengjie Name: selectById Type: PROCEDURE Definer: root@localhost Modified: 2019-10-28 21:21:37 Created: 2019-10-28 21:21:37 Security_type: DEFINER Comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci Database Collation: utf8_general_ci *************************** 6. row *************************** Db: yinzhengjie Name: showTime Type: PROCEDURE Definer: root@localhost Modified: 2019-10-28 20:49:09 Created: 2019-10-28 20:49:09 Security_type: DEFINER Comment: character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci Database Collation: utf8_general_ci 6 rows in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
3>.查看存储过程定义
MariaDB [yinzhengjie]> SHOW CREATE PROCEDURE showTime\G *************************** 1. row *************************** Procedure: showTime sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION Create Procedure: CREATE DEFINER=`root`@`localhost` PROCEDURE `showTime`() BEGIN SELECT now(); END character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci Database Collation: utf8_general_ci 1 row in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> SHOW CREATE PROCEDURE selectById\G *************************** 1. row *************************** Procedure: selectById sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION Create Procedure: CREATE DEFINER=`root`@`localhost` PROCEDURE `selectById`(IN uid SMALLINT UNSIGNED) BEGIN SELECT * FROM students WHERE stuid = uid; END character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci Database Collation: utf8_general_ci 1 row in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> SHOW CREATE PROCEDURE dorepeat\G *************************** 1. row *************************** Procedure: dorepeat sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION Create Procedure: CREATE DEFINER=`root`@`localhost` PROCEDURE `dorepeat`(n INT) BEGIN SET @i = 0; SET @sum = 0; REPEAT SET @sum = @sum+@i; SET @i = @i + 1; UNTIL @i > n END REPEAT; END character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci Database Collation: utf8_general_ci 1 row in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> SHOW CREATE PROCEDURE deleteById\G *************************** 1. row *************************** Procedure: deleteById sql_mode: STRICT_TRANS_TABLES,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION Create Procedure: CREATE DEFINER=`root`@`localhost` PROCEDURE `deleteById`(IN uid SMALLINT UNSIGNED, OUT num SMALLINT UNSIGNED)BEGIN DELETE FROM students WHERE stuid >= uid; SELECT row_count() into num; END character_set_client: utf8mb4 collation_connection: utf8mb4_general_ci Database Collation: utf8_general_ci 1 row in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
4>.调用存储过程
MariaDB [yinzhengjie]> CALL showTime; #当无参时,可以省略"()",当有参数时,不可省略"()” +---------------------+ | now() | +---------------------+ | 2019-10-28 21:27:04 | +---------------------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec) MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> SELECT * FROM students; +-------+---------------+-----+--------+---------+-----------+ | StuID | Name | Age | Gender | ClassID | TeacherID | +-------+---------------+-----+--------+---------+-----------+ | 1 | Shi Zhongyu | 22 | M | 2 | 3 | | 2 | Shi Potian | 22 | M | 1 | 7 | | 3 | Xie Yanke | 53 | M | 2 | 16 | | 4 | Ding Dian | 32 | M | 4 | 4 | | 5 | Yu Yutong | 26 | M | 3 | 1 | | 6 | Shi Qing | 46 | M | 5 | NULL | | 7 | Xi Ren | 19 | F | 3 | NULL | | 8 | Lin Daiyu | 17 | F | 7 | NULL | | 9 | Ren Yingying | 20 | F | 6 | NULL | | 10 | Yue Lingshan | 19 | F | 3 | NULL | | 11 | Yuan Chengzhi | 23 | M | 6 | NULL | | 12 | Wen Qingqing | 19 | F | 1 | NULL | | 13 | Tian Boguang | 33 | M | 2 | NULL | | 14 | Lu Wushuang | 17 | F | 3 | NULL | | 18 | Hua Rong | 23 | M | 7 | NULL | | 19 | Xue Baochai | 18 | F | 6 | NULL | | 20 | Diao Chan | 19 | F | 7 | NULL | | 21 | Huang Yueying | 22 | F | 6 | NULL | | 22 | Xiao Qiao | 20 | F | 1 | NULL | | 23 | Ma Chao | 23 | M | 4 | NULL | | 24 | Xu Xian | 27 | M | NULL | NULL | | 25 | Sun Dasheng | 100 | M | NULL | NULL | +-------+---------------+-----+--------+---------+-----------+ 22 rows in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> call selectById(20); +-------+-----------+-----+--------+---------+-----------+ | StuID | Name | Age | Gender | ClassID | TeacherID | +-------+-----------+-----+--------+---------+-----------+ | 20 | Diao Chan | 19 | F | 7 | NULL | +-------+-----------+-----+--------+---------+-----------+ 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> CALL dorepeat(200); Query OK, 0 rows affected (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> SELECT @sum; +-------+ | @sum | +-------+ | 20100 | +-------+ 1 row in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> SELECT @i; +------+ | @i | +------+ | 201 | +------+ 1 row in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
MariaDB [yinzhengjie]> SELECT * FROM students; +-------+---------------+-----+--------+---------+-----------+ | StuID | Name | Age | Gender | ClassID | TeacherID | +-------+---------------+-----+--------+---------+-----------+ | 1 | Shi Zhongyu | 22 | M | 2 | 3 | | 2 | Shi Potian | 22 | M | 1 | 7 | | 3 | Xie Yanke | 53 | M | 2 | 16 | | 4 | Ding Dian | 32 | M | 4 | 4 | | 5 | Yu Yutong | 26 | M | 3 | 1 | | 6 | Shi Qing | 46 | M | 5 | NULL | | 7 | Xi Ren | 19 | F | 3 | NULL | | 8 | Lin Daiyu | 17 | F | 7 | NULL | | 9 | Ren Yingying | 20 | F | 6 | NULL | | 10 | Yue Lingshan | 19 | F | 3 | NULL | | 11 | Yuan Chengzhi | 23 | M | 6 | NULL | | 12 | Wen Qingqing | 19 | F | 1 | NULL | | 13 | Tian Boguang | 33 | M | 2 | NULL | | 14 | Lu Wushuang | 17 | F | 3 | NULL | | 18 | Hua Rong | 23 | M | 7 | NULL | | 19 | Xue Baochai | 18 | F | 6 | NULL | | 20 | Diao Chan | 19 | F | 7 | NULL | | 21 | Huang Yueying | 22 | F | 6 | NULL | | 22 | Xiao Qiao | 20 | F | 1 | NULL | | 23 | Ma Chao | 23 | M | 4 | NULL | | 24 | Xu Xian | 27 | M | NULL | NULL | | 25 | Sun Dasheng | 100 | M | NULL | NULL | +-------+---------------+-----+--------+---------+-----------+ 22 rows in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> CALL deleteById(2,@Line); Query OK, 1 row affected (0.01 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> SELECT @Line; +-------+ | @Line | +-------+ | 21 | +-------+ row in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> SELECT * FROM students; +-------+-------------+-----+--------+---------+-----------+ | StuID | Name | Age | Gender | ClassID | TeacherID | +-------+-------------+-----+--------+---------+-----------+ | 1 | Shi Zhongyu | 22 | M | 2 | 3 | +-------+-------------+-----+--------+---------+-----------+ row in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]>
5>.存储过程修改
ALTER语句修改存储过程只能修改存储过程的注释等无关紧要的东西,不能修改存储过程体,所以要修改存储过程,方法就是删除重建
6>.删除存储过程
MariaDB [yinzhengjie]> SHOW PROCEDURE STATUS; +-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+| Db | Name | Type | Definer | Modified | Created | Security_type | Comment | character _set_client | collation_connection | Database Collation |+-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+| mysql | AddGeometryColumn | PROCEDURE | root@localhost | 2019-10-26 22:17:15 | 2019-10-26 22:17:15 | DEFINER | | utf8 | utf8_general_ci | latin1_swedish_ci || mysql | DropGeometryColumn | PROCEDURE | root@localhost | 2019-10-26 22:17:15 | 2019-10-26 22:17:15 | DEFINER | | utf8 | utf8_general_ci | latin1_swedish_ci || yinzhengjie | deleteById | PROCEDURE | root@localhost | 2019-10-28 21:23:31 | 2019-10-28 21:23:31 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci || yinzhengjie | dorepeat | PROCEDURE | root@localhost | 2019-10-28 21:32:01 | 2019-10-28 21:32:01 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci || yinzhengjie | selectById | PROCEDURE | root@localhost | 2019-10-28 21:21:37 | 2019-10-28 21:21:37 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci || yinzhengjie | showTime | PROCEDURE | root@localhost | 2019-10-28 20:49:09 | 2019-10-28 20:49:09 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci |+-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+6 rows in set (0.00 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> DROP PROCEDURE IF EXISTS deleteById; Query OK, 0 rows affected (0.01 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> DROP PROCEDURE IF EXISTS selectById; Query OK, 0 rows affected (0.01 sec) MariaDB [yinzhengjie]> MariaDB [yinzhengjie]> SHOW PROCEDURE STATUS; +-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+| Db | Name | Type | Definer | Modified | Created | Security_type | Comment | character _set_client | collation_connection | Database Collation |+-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+| mysql | AddGeometryColumn | PROCEDURE | root@localhost | 2019-10-26 22:17:15 | 2019-10-26 22:17:15 | DEFINER | | utf8 | utf8_general_ci | latin1_swedish_ci || mysql | DropGeometryColumn | PROCEDURE | root@localhost | 2019-10-26 22:17:15 | 2019-10-26 22:17:15 | DEFINER | | utf8 | utf8_general_ci | latin1_swedish_ci || yinzhengjie | dorepeat | PROCEDURE | root@localhost | 2019-10-28 21:32:01 | 2019-10-28 21:32:01 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci || yinzhengjie | showTime | PROCEDURE | root@localhost | 2019-10-28 20:49:09 | 2019-10-28 20:49:09 | DEFINER | | utf8mb4 | utf8mb4_general_ci | utf8_general_ci |+-------------+--------------------+-----------+----------------+---------------------+---------------------+---------------+---------+---------- ------------+----------------------+--------------------+4 rows in set (0.00 sec) MariaDB [yinzhengjie]>
7>.流程控制
存储过程和函数中可以使用流程控制来控制语句的执行 流程控制： IF： 用来进行条件判断。根据是否满足条件，执行不同语句 CASE： 用来进行条件判断，可实现比IF语句更复杂的条件判断 LOOP： 重复执行特定的语句，实现一个简单的循环 LEAVE： 用于跳出循环控制 ITERATE： 跳出本次循环，然后直接进入下一次循环 REPEAT： 有条件控制的循环语句。当满足特定条件时，就会跳出循环语句 WHILE： 有条件控制的循环语句
本文来自博客园，作者：尹正杰，转载请注明原文链接：https://www.cnblogs.com/yinzhengjie/p/11750172.html，个人微信: "JasonYin2020"（添加时请备注来源及意图备注，有偿付费）
当你的才华还撑不起你的野心的时候，你就应该静下心来学习。当你的能力还驾驭不了你的目标的时候，你就应该沉下心来历练。问问自己，想要怎样的人生。
