从我表中的两列开始,我想获得这些列中值的统一计数.例如,两列是:
表:报告
| type | place |
-----------------------------------------
| one | home |
| two | school |
| three | work |
| four | cafe |
| five | friends |
| six | mall |
| one | work |
| one | work |
| three | work |
| two | cafe |
| five | cafe |
| one | home |
如果我这样做:SELECT类型,按类型从报告组计数(*)
我明白了:
| type | count |
-----------------------------
| one | 4 …