在SQL中将两个查询合并为一个查询

Question

In my file there is already one query name query1 and I write another query name query2 . The o/p of both query is userid . Now I want to find the common userid from these two queries. So is there any function for that?

The array_intersect() function generates an error.

Answer 1

Use a JOIN

$query1 = "SELECT userid FROM table1";
$query2 = "SELECT userid FROM table2 WHERE something = 10";
$joinQuery = "
    SELECT a.userid
    FROM ($query1) AS a
    JOIN ($query2) AS b
    ON a.userid = b.userid";