MySQL动态列转行的实现示例

# 创建用户表
DROP TABLE IF EXISTS users;
CREATE TABLE users
(
    id          INT PRIMARY KEY auto_increment COMMENT '主键',
    username    VARCHAR(30) NOT NULL COMMENT '用户名',
    password    VARCHAR(30) NOT NULL COMMENT '密码',
    nickname    VARCHAR(30) COMMENT '昵称',
    phone       VARCHAR(11) COMMENT '电话号码',
    create_time DATETIME DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
    update_time DATETIME DEFAULT CURRENT_TIMESTAMP COMMENT '更新时间',
    is_deleted  INT      DEFAULT 0 COMMENT '逻辑删除(1:已删除，0:未删除)'
) COMMENT '用户信息表';

# 插入数据
INSERT INTO users (username, password, nickname, phone, create_time)
VALUES ('admin', 'admin', '张三', '18955554444', '2023-05-01 22:48:11'),
       ('root', 'root', '李四', '17755624235', '2023-05-02 22:48:11'),
       ('lisi', 'lisi', '王五', '15989654123', '2023-05-03 22:48:11'),
       ('lucky', 'lucky', '赵六', '19956852548', '2023-05-04 22:48:11'),
       ('admin2', 'admin', '张三', '18955554444', '2023-05-01 22:48:11'),
       ('root2', 'root', '李四', '17755624235', '2023-05-02 22:48:11'),
       ('lisi2', 'lisi', '王五', '15989654123', '2023-05-01 22:48:11'),
       ('lucky2', 'lucky', '赵六', '19956852548', '2023-05-01 22:48:11');

select DATE_FORMAT(create_time,'%Y/%m/%d') as create_date, count(*) as sum from users group by create_date

SELECT
	SUM( DATE_FORMAT( create_time, '%Y/%m/%d' ) = '2023/05/01' ) AS '2023/05/01',
	SUM( DATE_FORMAT( create_time, '%Y/%m/%d' ) = '2023/05/02' ) AS '2023/05/02',
	SUM( DATE_FORMAT( create_time, '%Y/%m/%d' ) = '2023/05/03' ) AS '2023/05/03',
	SUM( DATE_FORMAT( create_time, '%Y/%m/%d' ) = '2023/05/04' ) AS '2023/05/04' 
FROM
	users

# 设置结束分隔符
DELIMITER $$
# 判断定义的存储过程是否存在，存在删除，以防存储过程存在报错
DROP PROCEDURE IF EXISTS pro$$ 
# 创建存储过程
CREATE PROCEDURE pro () BEGIN
  # 定义一个变量
  SET @SQL = NULL;
	# 把查询的日期赋给变量
	# 这里需要将日期格式化一下, 我要的格式是yyyy/MM/dd,
	# 而数据给我们的是yyyy-MM-dd HH:mm:ss
	SELECT
		GROUP_CONCAT( DISTINCT CONCAT( 'SUM(DATE_FORMAT(create_time, \'%Y/%m/%d\') = ''', 
		DATE_FORMAT( create_time, '%Y/%m/%d' ), ''') AS ''',          
		DATE_FORMAT( create_time, '%Y/%m/%d' ), '''' ) ) INTO @SQL 
	FROM users;
	# 注意：如果运行时报错可以执行
	# SELECT @SQL;
	# 检查拼接的SQL是否正确
	# 拼接sql
	SET @SQL = concat( 'select ', @SQL, ' from users' );
	# 预处理语句
	PREPARE stmt FROM	@SQL;
	# 执行
	EXECUTE stmt;
	# 销毁
	DEALLOCATE PREPARE stmt;
# 结束
END $$ 

 # 调用存储过程
CALL pro ();

INSERT INTO users (username, password, nickname, phone, create_time)
VALUES ('test', 'test', 'test', '18955554844', '2023-05-08 22:48:11');