[MySql] SELECT statements have a different number of columns in UNION Query

Hi Friends,

I was working with website with millions of records where I need to use UNION SQL Query. I used the UNION SQL query and try to execute it but it shows me below error message.

The used SELECT statements have a different number of columns.

UNION SQL Query

$sql = "(SELECT id, name FROM user) UNION (SELECT * FROM user_reg) ORDER BY id DESC";

Reason why it give me error “The used SELECT statements have a different number of columns.” is, columns does not match in result of both query. If you see first query, i try to get id and name column. In second query, i try to get all columns. So it throws this error.

If you want to use UNION SQL Query, you should match the column of both tables. I hope this helps you.