MySQL--utf8mb4与等值查询测试

测试脚本

## 删除测试表
DROP TABLE IF EXISTS tb2001;
DROP TABLE IF EXISTS tb2002;
DROP TABLE IF EXISTS tb2003;

## 创建测试表
CREATE TABLE tb2001(
id INT AUTO_INCREMENT PRIMARY KEY,
c1 VARCHAR(100) COLLATE utf8mb4_unicode_ci,
c2 VARCHAR(100) COLLATE utf8mb4_bin
)ENGINE=INNODB DEFAULT CHARSET=utf8mb4 ;

CREATE TABLE tb2002(
id INT AUTO_INCREMENT PRIMARY KEY,
c1 VARCHAR(100) COLLATE utf8mb4_general_ci,
c2 VARCHAR(100) COLLATE utf8mb4_bin
)ENGINE=INNODB DEFAULT CHARSET=utf8mb4;

CREATE TABLE tb2003(
id INT AUTO_INCREMENT PRIMARY KEY,
c1 VARCHAR(100) COLLATE utf8mb4_0900_ai_ci,
c2 VARCHAR(100) COLLATE utf8mb4_bin
)ENGINE=INNODB DEFAULT CHARSET=utf8mb4;

## 插入测试数据
INSERT INTO tb2001(c1,c2)VALUES(0xF09F8D83,0xF09F8D83),(0xF09FA68A,0xF09FA68A),(0xF09F8CA0,0xF09F8CA0);
INSERT INTO tb2002(c1,c2)VALUES(0xF09F8D83,0xF09F8D83),(0xF09FA68A,0xF09FA68A),(0xF09F8CA0,0xF09F8CA0);
INSERT INTO tb2003(c1,c2)VALUES(0xF09F8D83,0xF09F8D83),(0xF09FA68A,0xF09FA68A),(0xF09F8CA0,0xF09F8CA0);

## 等值查询测试
SELECT * FROM tb2001 WHERE c1=0xF09F8D83;
SELECT * FROM tb2002 WHERE c1=0xF09F8D83;
SELECT * FROM tb2003 WHERE c1=0xF09F8D83;

SELECT * FROM tb2001 WHERE c2=0xF09F8D83;
SELECT * FROM tb2002 WHERE c2=0xF09F8D83;
SELECT * FROM tb2003 WHERE c2=0xF09F8D83;

测试结果

mysql> SELECT * FROM tb2001 WHERE c1=0xF09F8D83;
+----+------+------+
| id | c1   | c2   |
+----+------+------+
|  1 | 🍃     | 🍃     |
|  2 | 🦊     | 🦊     |
|  3 | 🌠     | 🌠     |
+----+------+------+
3 rows in set (0.00 sec)

mysql> SELECT * FROM tb2002 WHERE c1=0xF09F8D83;
+----+------+------+
| id | c1   | c2   |
+----+------+------+
|  1 | 🍃     | 🍃     |
|  2 | 🦊     | 🦊     |
|  3 | 🌠     | 🌠     |
+----+------+------+
3 rows in set (0.01 sec)

mysql> SELECT * FROM tb2003 WHERE c1=0xF09F8D83;
+----+------+------+
| id | c1   | c2   |
+----+------+------+
|  1 | 🍃     | 🍃     |
+----+------+------+
1 row in set (0.00 sec)

mysql> 
mysql> SELECT * FROM tb2001 WHERE c2=0xF09F8D83;
+----+------+------+
| id | c1   | c2   |
+----+------+------+
|  1 | 🍃     | 🍃     |
+----+------+------+
1 row in set (0.00 sec)

mysql> SELECT * FROM tb2002 WHERE c2=0xF09F8D83;
+----+------+------+
| id | c1   | c2   |
+----+------+------+
|  1 | 🍃     | 🍃     |
+----+------+------+
1 row in set (0.00 sec)

mysql> SELECT * FROM tb2003 WHERE c2=0xF09F8D83;
+----+------+------+
| id | c1   | c2   |
+----+------+------+
|  1 | 🍃     | 🍃     |
+----+------+------+
1 row in set (0.00 sec)

测试总结

• 使用utf8mb4字符集能存储特殊字符如表情符号。
• utf8mb4_unicode_ci和utf8mb4_general_ci排序规则无法"正确匹配"特殊字符。
• utf8mb4_0900_ai_ci排序规则能"正确匹配"特殊字符,但仅适用MySQL 8.0版本。
• utf8mb4_bin排序规则基于二级制方式匹配特殊字符，能"正确匹配"特殊字符，适用于MySQL各个版本。