In SQL we can use a subquery in several parts of the query. We can use a subquery in the WHERE clause (which is the natural place for the subquery), in the FROM clause, in the SELECT list, or even in the HAVING clause. Moreover, we can use subqueries in the UPDATE, DELETE and INSERT statements. However, in this article, we will focus on subqueries used in the WHERE clause and especially on the operator used to compare the results of the subquery.
THE EASY EXAMPLE
The first example ...
Correlated Subqueries With TeamSQL
Correlated subqueries are a different type of subqueries. In some situations, you must use a correlated subquery to obtain the correct reply or result data set. In this article, we will cover how to identify or detect these situations in which you must use a correlated subquery. We also show some examples of correlated subqueries, and we will even talk about how to avoid overusing correlated subqueries.
IN WHAT SITUATIONS NEED CORRELATED SUBQUERIES?
There are some data questions ...