Sub-query

Where Can Sub-query be placed in?

After WHERE

SELECT * FROM [table]
WHERE [column] [operator] [sub_query]

In SELECT Statement

SELECT 
    [column1],
    [column2],
    (SELECT [column]
        FROM [table]) AS [alias]
FROM [table]

After FROM

SELECT *
FROM [sub_query]

• Use view to represent temporary table when the sub-query is complex.