mysql - 我如何获得这三个 COUNTS() 的总和？

Question

这是我的查询:

SELECT (SELECT COUNT(`id`) FROM `table1` WHERE `id` = '1') AS `count1`,
(SELECT COUNT(`id`) FROM `table2` WHERE `id` = '1') AS `count2`,
(SELECT COUNT(`id`) FROM `table3` WHERE `id` = '1') AS `count3`

如何得到 count1, count2, count3 的总和？

有什么方法可以在上面的查询中吗？

Answer 1

当然。只需将这些值加在一起:

SELECT (SELECT COUNT(`id`) FROM `table1` WHERE `id` = '1') +
       (SELECT COUNT(`id`) FROM `table2` WHERE `id` = '1') +
       (SELECT COUNT(`id`) FROM `table3` WHERE `id` = '1') AS `sum` ...