Question

I have two table category and subcategory
I am trying to delete record from this table using mysql query

Query is=

$sql="Delete t1, t2 From category as t1 
       INNER JOIN  subcategory as t2 on t1.c_id = t2.c_id
       WHERE t1.c_id='$del_c_id' ";

This query only delete row from category(t1) whose primary key used into subcategory(t2) table.

Not delete row from category(t1) whose primary key not used in subcategory(t2).

Answer 1

You need to use a LEFT JOIN instead of INNER JOIN. By definition LEFT JOIN returns all results from t1, even if they don’t have a match in t2.

See this link for more info on join types:
http://www.codinghorror.com/blog/2007/10/a-visual-explanation-of-sql-joins.html