mysql - 单个查询中的多个 select 语句

Question

我正在 php (mysql) 中生成报告，

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 table 。

我可以在单个查询中完成它吗？如果我这样做了？进程变慢？

Answer 1

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