我有这些疑问。
Yii::app()->db->createCommand("SELECT SUM(comment) FROM `tbl_1` t1 LEFT JOIN `tbl_2` t2 on t1.id_id = t2.id WHERE create_time >= UNIX_TIMESTAMP(NOW() - INTERVAL 1 DAY)")->queryScalar();
Yii::app()->db->createCommand("SELECT SUM(comment) FROM `tbl_1` t1 LEFT JOIN `tbl_2` t2 on t1.id_id = t2.id WHERE create_time >= UNIX_TIMESTAMP(NOW() - INTERVAL 1 WEEK)")->queryScalar();
Yii::app()->db->createCommand("SELECT SUM(comment) FROM `tbl_1` t1 LEFT JOIN `tbl_2` t2 on t1.id_id = t2.id WHERE create_time >= UNIX_TIMESTAMP(NOW() - INTERVAL 1 MONTH)")->queryScalar();
如何在一个查询中编写此内容?
最佳答案
正如 @geoandri 所说,条件重叠,因此仅在一个查询中获取该查询的唯一方法是使用子查询的联合,但这样做不会获得任何性能。
关于mysql - SQL合并查询,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26382954/