MySQL中的CONCAT函数使用教程

前端技术 2023/09/08 MYSQL

使用MySQL CONCAT()函数将两个字符串连接起来，形成一个单一的字符串。试试下面的例子：

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

了解CONCAT函数更详细，考虑EMPLOYEE_TBL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)

可以用以下命令连结上表中的name和ID：

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)


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