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Asked 3 years ago
17 Jun 2021
Views 278
Stefanie

Stefanie posted

Putting another query inside the where clause mysql and php

Putting another query inside the where clause mysql and php
shyam

shyam
answered Apr 28 '23 00:00

You can use a subquery inside the WHERE clause of a MySQL query to filter the results based on the output of another query. Here's an example using PHP:



$subquery = "SELECT id FROM other_table WHERE column1 = 'value'";
$query = "SELECT * FROM my_table WHERE id IN ($subquery)";

$result = mysqli_query($connection, $query);

In this example, $subquery is the subquery that selects the id values from other_table where column1 is equal to 'value'. The $query variable uses the IN operator to filter the results of my_table based on the id values returned by the subquery.

Note that in order to use a subquery in the WHERE clause, the subquery must return a single column with one or more rows. Also, make sure to properly escape and sanitize any user input used in the subquery to prevent SQL injection attacks
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