我需要从不同表中检索具有不同条件的多个列。 什么,我有如下SQL查询:检索具有不同条件的列
SELECT
(SELECT COUNT(*) FROM Table1 WHERE Price >= 0 Price < 10) AS 'Group1',
(SELECT COUNT(*) FROM Table1 WHERE Price >= 10 AND Price < 20) AS 'Group2',
(SELECT COUNT(*) FROM Table1 WHERE Price >= 20 AND Price < 30) AS 'Group3',
(SELECT COUNT(*) FROM Table2 WHERE Price >= 0 Price < 10) AS 'Group4',
(SELECT COUNT(*) FROM Table2 WHERE Price >= 10 AND Price < 20) AS 'Group5',
(SELECT COUNT(*) FROM Table2 WHERE Price >= 20 AND Price < 30) AS 'Group6'
只是想知道有没有什么更好的方式来重组为上述条件更好的查询?
为什么好,有什么区别?问题中还有2个表格。 – Alex 2013-04-10 06:10:23
@Alexey它只会传递一次表格,而不是调用6'SELECT'语句 – 2013-04-10 06:12:30
@J W但由于价格限制,它不会执行全面扫描。所以在一起看起来都一样。 – Alex 2013-04-10 06:14:17