MySQL CONCAT 函数

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  CONCAT 函数

  MySQL CONCAT函数用于连接两个字符串以形成单个字符串。尝试以下示例-

  mmysql> SELECT CONCAT('FIRST ', 'SECOND');
  +----------------------------+
  | CONCAT('FIRST ', 'SECOND') |
  +----------------------------+
  |        FIRST SECOND        |
  +----------------------------+
  1 row in set (0.00 sec)
  

  为了更详细地了解CONCAT函数，请考虑一个employee_tbl表，该表具有以下记录-

  mysql> SELECT * FROM employee_tbl;
  +------+------+------------+--------------------+
  |  id  | name | work_date  | daily_typing_pages |
  +------+------+------------+--------------------+
  |   1  | John | 2007-01-24 |        250         |
  |   2  | Ram  | 2007-05-27 |        220         |
  |   3  | Jack | 2007-05-06 |        170         |
  |   3  | Jack | 2007-04-06 |        100         |
  |   4  | Jill | 2007-04-06 |        220         |
  |   5  | Zara | 2007-06-06 |        300         |
  |   5  | Zara | 2007-02-06 |        350         |
  +------+------+------------+--------------------+
  7 rows in set (0.00 sec)

  现在，假设您要基于上表将所有名称employee ID和work_date串联起来，那么您可以使用以下命令进行操作

  mysql> SELECT CONCAT(id, name, work_date)
     -> FROM employee_tbl;
  +-----------------------------+
  | CONCAT(id, name, work_date) |
  +-----------------------------+
  |      1John2007-01-24        |
  |      2Ram2007-05-27         |
  |      3Jack2007-05-06        |
  |      3Jack2007-04-06        |
  |      4Jill2007-04-06        |
  |      5Zara2007-06-06        |
  |      5Zara2007-02-06        |
  +-----------------------------+
  7 rows in set (0.00 sec)