Example of using Subquery in MS SQL Server

Use of subquery with FROM Clause: Use alias name otherwise it gives an error.

SELECT * FROM (select * from [Person].[CountryRegion]) k 

Use of subquery with IN Clause in where condition:

SELECT * FROM  [Person].[Address] where 
StateProvinceID in (select StateProvinceID from  [Person].[StateProvince] where 
Name = 'Alberta')

Use Subquery as a column

select Addressline1, city, (select name from  [Person].[StateProvince] where 
StateProvinceID = a.StateProvinceID) as State from [Person].[Address]  a

Use SubQuery with IN Insert operation:

INSERT INTO temp SELECT * FROM [Person].[Address]