单个查询中的多个选择语句 [英] Multiple select statements in Single query

问题描述

我正在用php(mysql)生成报告，

I am generating a report in php (mysql),

例如:

`select count(id) as tot_user from user_table
 select count(id) as tot_cat from cat_table
 select count(id) as tot_course from course_table`

像这样，我有12张桌子.

Like this I have 12 tables.

我可以在单个查询中进行查询吗?如果我做到了?过程变慢了吗?

Can i make it in single query. If i did? Process gets slow?

推荐答案

SELECT  (
    SELECT COUNT(*)
    FROM   user_table
    ) AS tot_user,
    (
    SELECT COUNT(*)
    FROM   cat_table
    ) AS tot_cat,
    (
    SELECT COUNT(*)
    FROM   course_table
    ) AS tot_course

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