mysql 查询实现,将9条数据的一个字段取出来,分别放进9个字段中
时间: 2023-12-10 13:42:10 浏览: 23
这个需求可以通过MySQL的`CASE WHEN`语句实现,示例代码如下:
```sql
SELECT
MAX(CASE WHEN id = 1 THEN field_name ELSE NULL END) AS field_name_1,
MAX(CASE WHEN id = 2 THEN field_name ELSE NULL END) AS field_name_2,
MAX(CASE WHEN id = 3 THEN field_name ELSE NULL END) AS field_name_3,
MAX(CASE WHEN id = 4 THEN field_name ELSE NULL END) AS field_name_4,
MAX(CASE WHEN id = 5 THEN field_name ELSE NULL END) AS field_name_5,
MAX(CASE WHEN id = 6 THEN field_name ELSE NULL END) AS field_name_6,
MAX(CASE WHEN id = 7 THEN field_name ELSE NULL END) AS field_name_7,
MAX(CASE WHEN id = 8 THEN field_name ELSE NULL END) AS field_name_8,
MAX(CASE WHEN id = 9 THEN field_name ELSE NULL END) AS field_name_9
FROM table_name;
```
其中,`field_name`是要取出来的字段名,`table_name`是要查询的表名,`id`是用来区分9条数据的字段名。这个查询会将`field_name`分别放进`field_name_1`到`field_name_9`这9个字段中,如果某个id对应的数据不存在,则相应的字段值为NULL。