題目:一張表:mysql
CREATE TABLE `tbl_time` (sql
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,spa
`time` char(10) NOT NULL DEFAULT '',io
PRIMARY KEY (`id`)select
) ENGINE=InnoDB;nio
mysql> select * from tbl_time;im
+----+------------+ant
| id | time |co
+----+------------+join
| 1 | 2015-10-27 |
| 2 | 2015-10-27 |
+----+------------+
可是我指望的結果是
2015-10-27,2015-10-28,2015-10-29,2015-10-30的2,0,0,0
並且只能用sql 語句
解決:
mysql> select a.tmp,if(time is null,0,count(*))as ant from (select '2015-10-27' as tmp union select '2015-10-28' union select '2015-10-29' union select '2015-10-30') a left join tbl_time on a.tmp=tbl_time.time group by a.tmp;
+------------+-----+
| tmp | ant |
+------------+-----+
| 2015-10-27 | 2 |
| 2015-10-28 | 0 |
| 2015-10-29 | 0 |
| 2015-10-30 | 0 |
+------------+-----+