转：ibatis常用16条SQL语句

1.输入参数为单个值

<delete id="com.fashionfree.stat.accesslog.deleteMemberAccessLogsBefore"    
 parameterClass="long">    
 delete from    
 MemberAccessLog    
 where    
 accessTimestamp = #value#    
 </delete>   

 <delete id="com.fashionfree.stat.accesslog.deleteMemberAccessLogsBefore"   
 parameterClass="long">   
 delete from   
 MemberAccessLog   
 where   
 accessTimestamp = #value#   
 </delete>

2.输入参数为一个对象

<insert id="com.fashionfree.stat.accesslog.MemberAccessLog.insert"    
 parameterClass="com.fashionfree.stat.accesslog.model.MemberAccessLog>    
 insert into MemberAccessLog    
 (    
 accessLogId, memberId, clientIP,    
 httpMethod, actionId, requestURL,    
 accessTimestamp, extend1, extend2,    
 extend3    
 )    
 values    
 (    
 #accessLogId#, #memberId#,    
 #clientIP#, #httpMethod#,    
 #actionId#, #requestURL#,    
 #accessTimestamp#, #extend1#,    
 #extend2#, #extend3#    
 )    
 </insert>   

 <insert id="com.fashionfree.stat.accesslog.MemberAccessLog.insert"   
 parameterClass="com.fashionfree.stat.accesslog.model.MemberAccessLog>   
 insert into MemberAccessLog   
 (   
 accessLogId, memberId, clientIP,   
 httpMethod, actionId, requestURL,   
 accessTimestamp, extend1, extend2,   
 extend3   
 )   
 values   
 (   
 #accessLogId#, #memberId#,   
 #clientIP#, #httpMethod#,   
 #actionId#, #requestURL#,   
 #accessTimestamp#, #extend1#,   
 #extend2#, #extend3#   
 )   
 </insert

3.输入参数为一个java.util.HashMap

<select id="com.fashionfree.stat.accesslog.selectActionIdAndActionNumber"    
 parameterClass="hashMap"    
 resultMap="getActionIdAndActionNumber">    
 select    
 actionId, count(*) as count    
 from    
 MemberAccessLog    
 where    
 memberId = #memberId#    
 and accessTimestamp &gt; #start#    
 and accessTimestamp &lt;= #end#    
 group by actionId    
 </select>

<select id="com.fashionfree.stat.accesslog.selectActionIdAndActionNumber"   
 parameterClass="hashMap"   
 resultMap="getActionIdAndActionNumber">   
 select   
 actionId, count(*) as count   
 from   
 MemberAccessLog   
 where   
 memberId = #memberId#   
 and accessTimestamp &gt; #start#   
 and accessTimestamp &lt;= #end#   
 group by actionId   
 </select>

4.输入参数中含有数组

<insert id="updateStatusBatch" parameterClass="hashMap">    
 update    
 Question    
 set    
 status = #status#    
 <dynamic prepend="where questionId in">    
 <isNotNull property="actionIds">    
 <iterate property="actionIds" open="(" close=")" conjunction=",">    
 #actionIds[]#    
 </iterate>    
 </isNotNull>    
 </dynamic>    
 </insert>   

 <insert id="updateStatusBatch" parameterClass="hashMap">   
 update   
 Question   
 set   
 status = #status#   
 <dynamic prepend="where questionId in">   
 <isNotNull property="actionIds">   
 <iterate property="actionIds" open="(" close=")" conjunction=",">   
 #actionIds[]#   
 </iterate>   
 </isNotNull>   
 </dynamic>   
 </insert>   

说明：actionIds为传入的数组的名字； 使用dynamic标签避免数组为空时导致sql语句语法出错； 使用isNotNull标签避免数组为null时ibatis解析出错

5.传递参数只含有一个数组

<select id="com.fashionfree.stat.accesslog.model.StatMemberAction.selectActionIdsOfModule"    
 resultClass="hashMap">    
 select    
 moduleId, actionId    
 from    
 StatMemberAction    
 <dynamic prepend="where moduleId in">    
 <iterate open="(" close=")" conjunction=",">    
 #[]#    
 </iterate>    
 </dynamic>    
 order by    
 moduleId    
 </select>

 <select id="com.fashionfree.stat.accesslog.model.StatMemberAction.selectActionIdsOfModule"   
 resultClass="hashMap">   
 select   
 moduleId, actionId   
 from   
 StatMemberAction   
 <dynamic prepend="where moduleId in">   
 <iterate open="(" close=")" conjunction=",">   
 #[]#   
 </iterate>   
 </dynamic>   
 order by   
 moduleId   
 </select>   

说明：注意select的标签中没有parameterClass一项

另：这里也可以把数组放进一个hashMap中，但增加额外开销，不建议使用

6.让ibatis把参数直接解析成字符串

<select id="com.fashionfree.stat.accesslog.selectSumDistinctCountOfAccessMemberNum"    
 parameterClass="hashMap" resultClass="int">    
 select    
 count(distinct memberId)    
 from    
 MemberAccessLog    
 where    
 accessTimestamp &gt;= #start#    
 and accessTimestamp &lt; #end#    
 and actionId in $actionIdString$    
 </select>  

 <select id="com.fashionfree.stat.accesslog.selectSumDistinctCountOfAccessMemberNum"   
 parameterClass="hashMap" resultClass="int">   
 select   
 count(distinct memberId)   
 from   
 MemberAccessLog   
 where   
 accessTimestamp &gt;= #start#   
 and accessTimestamp &lt; #end#   
 and actionId in $actionIdString$   
 </select>  

说明：使用这种方法存在sql注入的风险，不推荐使用

7.分页查询 (pagedQuery)

<select id="com.fashionfree.stat.accesslog.selectMemberAccessLogBy"    
 parameterClass="hashMap" resultMap="MemberAccessLogMap">    
 <include refid="selectAllSql"/>    
 <include refid="whereSql"/>    
 <include refid="pageSql"/>    
 </select>    
 <select id="com.fashionfree.stat.accesslog.selectMemberAccessLogBy.Count"    
 parameterClass="hashMap" resultClass="int">    
 <include refid="countSql"/>    
 <include refid="whereSql"/>    
 </select>    
 <sql id="selectAllSql">    
 select    
 accessLogId, memberId, clientIP,    
 httpMethod, actionId, requestURL,    
 accessTimestamp, extend1, extend2,    
 extend3    
 from    
 MemberAccessLog    
 </sql>    
 <sql id="whereSql">    
 accessTimestamp &lt;= #accessTimestamp#    
 </sql>    
 <sql id="countSql">    
 select    
 count(*)    
 from    
 MemberAccessLog    
 </sql>    
 <sql id="pageSql">    
 <dynamic>    
 <isNotNull property="startIndex">    
 <isNotNull property="pageSize">    
 limit #startIndex# , #pageSize#    
 </isNotNull>    
 </isNotNull>    
 </dynamic>    
 </sql>

 <select id="com.fashionfree.stat.accesslog.selectMemberAccessLogBy"   
 parameterClass="hashMap" resultMap="MemberAccessLogMap">   
 <include refid="selectAllSql"/>   
 <include refid="whereSql"/>   
 <include refid="pageSql"/>   
 </select>   
 <select id="com.fashionfree.stat.accesslog.selectMemberAccessLogBy.Count"   
 parameterClass="hashMap" resultClass="int">   
 <include refid="countSql"/>   
 <include refid="whereSql"/>   
 </select>   
 <sql id="selectAllSql">   
 select   
 accessLogId, memberId, clientIP,   
 httpMethod, actionId, requestURL,   
 accessTimestamp, extend1, extend2,   
 extend3   
 from   
 MemberAccessLog   
 </sql>   
 <sql id="whereSql">   
 accessTimestamp &lt;= #accessTimestamp#   
 </sql>   
 <sql id="countSql">   
 select   
 count(*)   
 from   
 MemberAccessLog   
 </sql>   
 <sql id="pageSql">   
 <dynamic>   
 <isNotNull property="startIndex">   
 <isNotNull property="pageSize">   
 limit #startIndex# , #pageSize#   
 </isNotNull>   
 </isNotNull>   
 </dynamic>   
 </sql>   

说明：本例中，代码应为：

    HashMap hashMap = new HashMap(); 
    hashMap.put(“accessTimestamp”, someValue); 
    pagedQuery(“com.fashionfree.stat.accesslog.selectMemberAccessLogBy”, hashMap); 

pagedQuery方法首先去查找名为com.fashionfree.stat.accesslog.selectMemberAccessLogBy.Count 的mapped statement来进行sql查询，从而得到com.fashionfree.stat.accesslog.selectMemberAccessLogBy查询的记录个数， 再进行所需的paged sql查询(com.fashionfree.stat.accesslog.selectMemberAccessLogBy)，具体过程参见utils类中的相关代码

8.sql语句中含有大于号>、小于号< 1. 将大于号、小于号写为： &gt; &lt; 如：

<delete id="com.fashionfree.stat.accesslog.deleteMemberAccessLogsBefore" parameterClass="long">    
 delete from    
 MemberAccessLog    
 where    
 accessTimestamp &lt;= #value#    
 </delete>   
 Xml代码  
 <delete id="com.fashionfree.stat.accesslog.deleteMemberAccessLogsBefore" parameterClass="long">   
 delete from   
 MemberAccessLog   
 where   
 accessTimestamp &lt;= #value#   
 </delete>   

    将特殊字符放在xml的CDATA区内：

 <delete id="com.fashionfree.stat.accesslog.deleteMemberAccessLogsBefore" parameterClass="long">    
 <![CDATA[   
 delete from   
 MemberAccessLog   
 where   
 accessTimestamp <= #value#   
 ]]>    
 </delete>   

 <delete id="com.fashionfree.stat.accesslog.deleteMemberAccessLogsBefore" parameterClass="long">   
 <![CDATA[  
 delete from  
 MemberAccessLog  
 where  
 accessTimestamp <= #value#  
 ]]>   
 </delete>   

推荐使用第一种方式，写为&lt; 和 &gt; (XML不对CDATA里的内容进行解析，因此如果CDATA中含有dynamic标签，将不起作用)

9.include和sql标签 将常用的sql语句整理在一起，便于共用：

<sql id="selectBasicSql">    
 select    
 samplingTimestamp,onlineNum,year,    
 month,week,day,hour    
 from    
 OnlineMemberNum    
 </sql>    
 <sql id="whereSqlBefore">    
 where samplingTimestamp &lt;= #samplingTimestamp#    
 </sql>    
 <select id="com.fashionfree.accesslog.selectOnlineMemberNumsBeforeSamplingTimestamp" parameterClass="hashmap" resultClass="OnlineMemberNum">    
 <include refid="selectBasicSql" />    
 <include refid="whereSqlBefore" />    
 </select>   

 <sql id="selectBasicSql">   
 select   
 samplingTimestamp,onlineNum,year,   
 month,week,day,hour   
 from   
 OnlineMemberNum   
 </sql>   
 <sql id="whereSqlBefore">   
 where samplingTimestamp &lt;= #samplingTimestamp#   
 </sql>   
 <select id="com.fashionfree.accesslog.selectOnlineMemberNumsBeforeSamplingTimestamp" parameterClass="hashmap" resultClass="OnlineMemberNum">   
 <include refid="selectBasicSql" />   
 <include refid="whereSqlBefore" />   
 </select>   

注意：sql标签只能用于被引用，不能当作mapped statement。如上例中有名为selectBasicSql的sql元素，试图使用其作为sql语句执行是错误的:

sqlMapClient.queryForList(“selectBasicSql”); ×

10.随机选取记录

<sql id=”randomSql”>   
 ORDER BY rand() LIMIT #number#   
 </sql>

从数据库中随机选取number条记录（只适用于MySQL）

11.将SQL GROUP BY分组中的字段拼接

<sql id=”selectGroupBy>    
 SELECT    
 a.answererCategoryId, a.answererId, a.answererName,    
 a.questionCategoryId, a.score, a.answeredNum,    
 a.correctNum, a.answerSeconds, a.createdTimestamp,    
 a.lastQuestionApprovedTimestamp, a.lastModified, GROUP_CONCAT(q.categoryName) as categoryName    
 FROM    
 AnswererCategory a, QuestionCategory q    
 WHERE a.questionCategoryId = q.questionCategoryId    
 GROUP BY a.answererId    
 ORDER BY a.answererCategoryId    
 </sql>

 <sql id=”selectGroupBy>   
 SELECT   
 a.answererCategoryId, a.answererId, a.answererName,   
 a.questionCategoryId, a.score, a.answeredNum,   
 a.correctNum, a.answerSeconds, a.createdTimestamp,   
 a.lastQuestionApprovedTimestamp, a.lastModified, GROUP_CONCAT(q.categoryName) as categoryName   
 FROM   
 AnswererCategory a, QuestionCategory q   
 WHERE a.questionCategoryId = q.questionCategoryId   
 GROUP BY a.answererId   
 ORDER BY a.answererCategoryId   
 </sql>  

注：SQL中使用了MySQL的GROUP_CONCAT函数

12.按照IN里面的顺序进行排序

①MySQL:

 <sql id=”groupByInArea”>    
 select    
 moduleId, moduleName,    
 status, lastModifierId, lastModifiedName,    
 lastModified    
 from    
 StatModule    
 where    
 moduleId in (3, 5, 1)    
 order by    
 instr(',3,5,1,' , ','+ltrim(moduleId)+',')    
 </sql>   

 <sql id=”groupByInArea”>   
 select   
 moduleId, moduleName,   
 status, lastModifierId, lastModifiedName,   
 lastModified   
 from   
 StatModule   
 where   
 moduleId in (3, 5, 1)   
 order by   
 instr(',3,5,1,' , ','+ltrim(moduleId)+',')   
 </sql>   

②SQLSERVER:

 <sql id=”groupByInArea”>    
 select    
 moduleId, moduleName,    
 status, lastModifierId, lastModifiedName,    
 lastModified    
 from    
 StatModule    
 where    
 moduleId in (3, 5, 1)    
 order by    
 charindex(','+ltrim(moduleId)+',' , ',3,5,1,')    
 </sql>  

 <sql id=”groupByInArea”>   
 select   
 moduleId, moduleName,   
 status, lastModifierId, lastModifiedName,   
 lastModified   
 from   
 StatModule   
 where   
 moduleId in (3, 5, 1)   
 order by   
 charindex(','+ltrim(moduleId)+',' , ',3,5,1,')   
 </sql>

说明：查询结果将按照moduleId在in列表中的顺序(3, 5, 1)来返回

MySQL : instr(str, substr)

SQLSERVER: charindex(substr, str) 返回字符串str 中子字符串的第一个出现位置 ltrim(str) 返回字符串str, 其引导(左面的)空格字符被删除

13.resultMap resultMap负责将SQL查询结果集的列值映射成Java Bean的属性值

<resultMap class="java.util.HashMap" id="getActionIdAndActionNumber">    
 <result column="actionId" property="actionId" jdbcType="BIGINT" javaType="long"/>    
 <result column="count" property="count" jdbcType="INT" javaType="int"/>    
 </resultMap>   
 Xml代码  
 <resultMap class="java.util.HashMap" id="getActionIdAndActionNumber">   
 <result column="actionId" property="actionId" jdbcType="BIGINT" javaType="long"/>   
 <result column="count" property="count" jdbcType="INT" javaType="int"/>   
 </resultMap>   

使用resultMap称为显式结果映射，与之对应的是resultClass(内联结果映射)，使用resultClass的最大好处便是简单、方便，不需显示指定结果，

由iBATIS根据反射来确定自行决定。而resultMap则可以通过指定jdbcType和javaType，提供更严格的配置认证。

14.typeAlias

<typeAlias alias="MemberOnlineDuration" type="com.fashionfree.stat.accesslog.model.MemberOnlineDuration" />    
 <typeAlias>

允许你定义别名，避免重复输入过长的名字

15.remap

<select id="testForRemap" parameterClass="hashMap" resultClass="hashMap" remapResults="true">    
 select    
 userId    
 <isEqual property="tag" compareValue="1">    
 , userName    
 </isEqual>    
 <isEqual property="tag" compareValue="2">    
 , userPassword    
 </isEqual>    
 from    
 UserInfo    
 </select>   

 <select id="testForRemap" parameterClass="hashMap" resultClass="hashMap" remapResults="true">   
 select   
 userId   
 <isEqual property="tag" compareValue="1">   
 , userName   
 </isEqual>   
 <isEqual property="tag" compareValue="2">   
 , userPassword   
 </isEqual>   
 from   
 UserInfo   
 </select>   

此例中，根据参数tag值的不同，会获得不同的结果集，如果没有remapResults="true"属性，iBatis会将第一次查询时的结果集缓存，下次再执行时（必须还是该进程中）不会再执行结果集映射，而是会使用缓存的结果集。

因此，如果上面的例子中remapResult为默认的false属性，而有一段程序这样书写：

 HashMap<String, Integer> hashMap = new HashMap<String, Integer>();    
 hashMap.put("tag", 1);    
 sqlClient.queryForList("testForRemap", hashMap);    
 hashMap.put("tag", 2);    
 sqlClient.queryForList("testForRemap", hashMap);   
 Java代码  
 HashMap<String, Integer> hashMap = new HashMap<String, Integer>();   
 hashMap.put("tag", 1);   
 sqlClient.queryForList("testForRemap", hashMap);   
 hashMap.put("tag", 2);   
 sqlClient.queryForList("testForRemap", hashMap);   

则程序会在执行最后一句的query查询时报错，原因就是iBATIS使用了第一次查询时的结果集，而前后两次的结果集是不同的:(userId, userName)和(userId, userPassword)，所以导致出错。如果使用了remapResults="true"这一属性，iBATIS会在每次执行查询时都执行结果集映射，从而避免错误的发生（此时会有较大的开销）。

16.dynamic标签的prepend dynamic标签的prepend属性作为前缀添加到结果内容前面，当标签的结果内容为空时，prepend属性将不起作用。

当dynamic标签中存在prepend属性时，将会把其嵌套子标签的第一个prepend属性忽略。例如：

 <sql id="whereSql">    
 <dynamic prepend="where ">    
 <isNotNull property="userId" prepend="BOGUS">    
 userId = #userId#    
 </isNotNull>    
 <isNotEmpty property="userName" prepend="and ">    
 userName = #userName#    
 </isNotEmpty>    
 </dynamic>    
 </sql>  

 <sql id="whereSql">   
 <dynamic prepend="where ">   
 <isNotNull property="userId" prepend="BOGUS">   
 userId = #userId#   
 </isNotNull>   
 <isNotEmpty property="userName" prepend="and ">   
 userName = #userName#   
 </isNotEmpty>   
 </dynamic>   
 </sql>  

此例中，dynamic标签中含有两个子标签<isNotNull>和<isNotEmpty>。根据前面叙述的原则，如果<isNotNull>标签中没有prepend="BOGUS" 这一假的属性来让dynamic去掉的话，<isNotEmpty>标签中的and就会被忽略，会造成sql语法错误。

注意：当dynamic标签没有prepend属性时，不会自动忽略其子标签的第一个prepend属性。