MySQL用注释当表头

# 若存储过程存在则删除
DROP PROCEDURE IF EXISTS sel;
# 创建一个存储过程
CREATE PROCEDURE sel(db VARCHAR(21845), tab VARCHAR(21845))
  # 开始内容
  BEGIN
    # 生成查询列注释放入 @colas 的语句
    SET @s = concat('
      SELECT group_concat(CASE COLUMN_COMMENT
                          WHEN \'\' THEN COLUMN_NAME
                          ELSE concat(COLUMN_NAME, \' AS \', COLUMN_COMMENT)
                          END SEPARATOR \', \') AS colas
      INTO @colas FROM information_schema.COLUMNS
      WHERE TABLE_SCHEMA = \'', db, '\' AND TABLE_NAME = \'', tab, '\'
    ');

    # 预编译、执行、释放
    PREPARE sel FROM @s;
    EXECUTE sel;
    DEALLOCATE PREPARE sel;

    # 拼接简单查询语句
    SET @s = concat('SELECT ', @colas, ' FROM ', db, '.', tab);

    PREPARE sel FROM @s;
    EXECUTE sel;
  END;

# 查询保存的 列名 AS 注释,
SELECT @colas;

# 使用例子 sel('数据库', '表');
CALL sel('test', 'job_depend');

# 预编译的语句再执行
EXECUTE sel;