subquery sql code example

Example 1: mssql subqueries

USE AdventureWorks2016;
GO
SELECT Ord.SalesOrderID, Ord.OrderDate,
    (SELECT MAX(OrdDet.UnitPrice)
     FROM Sales.SalesOrderDetail AS OrdDet
     WHERE Ord.SalesOrderID = OrdDet.SalesOrderID) AS MaxUnitPrice
FROM Sales.SalesOrderHeader AS Ord;
GO

Example 2: what is subquery in sql

SUBQUERY IS NESTED QUERY INSIDE A SELECT, 
INSERT OR UPDATE METHODS. OR INSIDE ANOTHER SUBQUERY

Example 3: why we use subquery in sql

We use subquery in order to get aggregate value in column without grouping data

Example 4: select in select sql

SELECT column1 = (SELECT column-name FROM table-name WHERE condition),       column-names  FROM table-name WEHRE condition

Example 5: subquery sql

UPDATE Book SET note= 'editore: ' + (SELECT name FROM Publisher WHERE Publisher.ID = Book.publisher)

Example 6: select in select sql

SELECT column-names  FROM table-name1 WHERE value IN (SELECT column-name                   FROM table-name2                   WHERE condition)