SELECT Examples (Transact-SQL)
This topic provides examples of using the SELECT statement.
The following example shows three code examples. This first code example returns all rows (no WHERE clause is specified) and all columns (using the *) from the Product table in the AdventureWorks2008R2 database.
This example returns all rows (no WHERE clause is specified), and only a subset of the columns (Name, ProductNumber, ListPrice) from the Product table in the AdventureWorks2008R2 database. Additionally, a column heading is added.
This example returns only the rows for Product that have a product line of R and that have days to manufacture that is less than 4.
The following first example creates a temporary table named #Bicycles in tempdb.
This second example creates the permanent table NewProducts.
USE AdventureWorks2008R2;
GO
IF OBJECT_ID ('dbo.NewProducts', 'U') IS NOT NULL
DROP TABLE dbo.NewProducts;
GO
ALTER DATABASE AdventureWorks2008R2 SET RECOVERY BULK_LOGGED;
GO
SELECT * INTO dbo.NewProducts
FROM Production.Product
WHERE ListPrice > $25
AND ListPrice < $100;
GO
ALTER DATABASE AdventureWorks2008R2 SET RECOVERY FULL;
GO
The following example shows queries that are semantically equivalent and illustrates the difference between using the EXISTS keyword and the IN keyword. Both are examples of a valid subquery that retrieves one instance of each product name for which the product model is a long sleeve logo jersey, and the ProductModelID numbers match between the Product and ProductModel tables.
USE AdventureWorks2008R2;
GO
SELECT DISTINCT Name
FROM Production.Product AS p
WHERE EXISTS
(SELECT *
FROM Production.ProductModel AS pm
WHERE p.ProductModelID = pm.ProductModelID
AND pm.Name LIKE 'Long-Sleeve Logo Jersey%');
GO
-- OR
USE AdventureWorks2008R2;
GO
SELECT DISTINCT Name
FROM Production.Product
WHERE ProductModelID IN
(SELECT ProductModelID
FROM Production.ProductModel
WHERE Name LIKE 'Long-Sleeve Logo Jersey%');
GO
The following example uses IN in a correlated, or repeating, subquery. This is a query that depends on the outer query for its values. The query is executed repeatedly, one time for each row that may be selected by the outer query. This query retrieves one instance of the first and last name of each employee for which the bonus in the SalesPerson table is 5000.00 and for which the employee identification numbers match in the Employee and SalesPerson tables.
The previous subquery in this statement cannot be evaluated independently of the outer query. It requires a value for Employee.BusinessEntityID, but this value changes as the SQL Server Database Engine examines different rows in Employee.
A correlated subquery can also be used in the HAVING clause of an outer query. This example finds the product models for which the maximum list price is more than twice the average for the model.
This example uses two correlated subqueries to find the names of employees who have sold a particular product.
USE AdventureWorks2008R2; GO SELECT DISTINCT pp.LastName, pp.FirstName FROM Person.Person pp JOIN HumanResources.Employee e ON e.BusinessEntityID = pp.BusinessEntityID WHERE pp.BusinessEntityID IN (SELECT SalesPersonID FROM Sales.SalesOrderHeader WHERE SalesOrderID IN (SELECT SalesOrderID FROM Sales.SalesOrderDetail WHERE ProductID IN (SELECT ProductID FROM Production.Product p WHERE ProductNumber = 'BK-M68B-42'))); GO
The first example that follows shows a HAVING clause with an aggregate function. It groups the rows in the SalesOrderDetail table by product ID and eliminates products whose average order quantities are five or less. The second example shows a HAVING clause without aggregate functions.
This query uses the LIKE clause in the HAVING clause.
USE AdventureWorks2008R2 ; GO SELECT SalesOrderID, CarrierTrackingNumber FROM Sales.SalesOrderDetail GROUP BY SalesOrderID, CarrierTrackingNumber HAVING CarrierTrackingNumber LIKE '4BD%' ORDER BY SalesOrderID ; GO
The following example groups the SalesOrderDetail table by product ID and includes only those groups of products that have orders totaling more than $1000000.00 and whose average order quantities are less than 3.
To see the products that have had total sales greater than $2000000.00, use this query:
If you want to make sure there are at least one thousand five hundred items involved in the calculations for each product, use HAVING COUNT(*) > 1500 to eliminate the products that return totals for fewer than 1500 items sold. The query looks like this:
The following example uses two code examples to show the use of COMPUTE BY. The first code example uses one COMPUTE BY with one aggregate function, and the second code example uses one COMPUTE BY item and two aggregate functions.
This query calculates the sum of the orders, for products with prices less than $5.00, for each type of product.
This query retrieves the product type and order total for products with unit prices under $5.00. The COMPUTE BY clause uses two different aggregate functions.
The COMPUTE keyword can be used without BY to generate grand totals, grand counts, and so on.
The following example finds the grand total of the prices and advances for all types of products les than $2.00.
You can use COMPUTE BY and COMPUTE without BY in the same query. The following query finds the sum of order quantities and line totals by product type, and then computes the grand total of order quantities and line totals.
The following example finds the sum of the prices of all orders whose unit price is less than $5 organized by product ID and order quantity, as well as the sum of the prices of all orders less than $5 organized by product ID only. You can use different aggregate functions in the same statement by including more than one COMPUTE BY clause.
The following example shows two ways to use the INDEX optimizer hint. The first example shows how to force the optimizer to use a nonclustered index to retrieve rows from a table, and the second example forces a table scan by using an index of 0.
USE AdventureWorks2008R2; GO SELECT pp.FirstName, pp.LastName, e.NationalIDNumber FROM HumanResources.Employee AS e WITH (INDEX(AK_Employee_NationalIDNumber)) JOIN Person.Person AS pp on e.BusinessEntityID = pp.BusinessEntityID WHERE LastName = 'Johnson'; GO -- Force a table scan by using INDEX = 0. USE AdventureWorks2008R2; GO SELECT pp.LastName, pp.FirstName, e.JobTitle FROM HumanResources.Employee AS e WITH (INDEX = 0) JOIN Person.Person AS pp ON e.BusinessEntityID = pp.BusinessEntityID WHERE LastName = 'Johnson'; GO
In the following example, the result set includes the contents of the ProductModelID and Name columns of both the ProductModel and Gloves tables.
USE AdventureWorks2008R2;
GO
IF OBJECT_ID ('dbo.Gloves', 'U') IS NOT NULL
DROP TABLE dbo.Gloves;
GO
-- Create Gloves table.
SELECT ProductModelID, Name
INTO dbo.Gloves
FROM Production.ProductModel
WHERE ProductModelID IN (3, 4);
GO
-- Here is the simple union.
USE AdventureWorks2008R2;
GO
SELECT ProductModelID, Name
FROM Production.ProductModel
WHERE ProductModelID NOT IN (3, 4)
UNION
SELECT ProductModelID, Name
FROM dbo.Gloves
ORDER BY Name;
GO
In the following example, the INTO clause in the second SELECT statement specifies that the table named ProductResults holds the final result set of the union of the designated columns of the ProductModel and Gloves tables. Note that the Gloves table is created in the first SELECT statement.
USE AdventureWorks2008R2;
GO
IF OBJECT_ID ('dbo.ProductResults', 'U') IS NOT NULL
DROP TABLE dbo.ProductResults;
GO
IF OBJECT_ID ('dbo.Gloves', 'U') IS NOT NULL
DROP TABLE dbo.Gloves;
GO
-- Create Gloves table.
SELECT ProductModelID, Name
INTO dbo.Gloves
FROM Production.ProductModel
WHERE ProductModelID IN (3, 4);
GO
USE AdventureWorks2008R2;
GO
SELECT ProductModelID, Name
INTO dbo.ProductResults
FROM Production.ProductModel
WHERE ProductModelID NOT IN (3, 4)
UNION
SELECT ProductModelID, Name
FROM dbo.Gloves;
GO
SELECT *
FROM dbo.ProductResults;
The order of certain parameters used with the UNION clause is important. The following example shows the incorrect and correct use of UNION in two SELECT statements in which a column is to be renamed in the output.
USE AdventureWorks2008R2;
GO
IF OBJECT_ID ('dbo.Gloves', 'U') IS NOT NULL
DROP TABLE dbo.Gloves;
GO
-- Create Gloves table.
SELECT ProductModelID, Name
INTO dbo.Gloves
FROM Production.ProductModel
WHERE ProductModelID IN (3, 4);
GO
/* INCORRECT */
USE AdventureWorks2008R2;
GO
SELECT ProductModelID, Name
FROM Production.ProductModel
WHERE ProductModelID NOT IN (3, 4)
ORDER BY Name
UNION
SELECT ProductModelID, Name
FROM dbo.Gloves;
GO
/* CORRECT */
USE AdventureWorks2008R2;
GO
SELECT ProductModelID, Name
FROM Production.ProductModel
WHERE ProductModelID NOT IN (3, 4)
UNION
SELECT ProductModelID, Name
FROM dbo.Gloves
ORDER BY Name;
GO
The following examples use UNION to combine the results of three tables that all have the same 5 rows of data. The first example uses UNION ALL to show the duplicated records, and returns all 15 rows. The second example uses UNION without ALL to eliminate the duplicate rows from the combined results of the three SELECT statements, and returns 5 rows.
The third example uses ALL with the first UNION and parentheses enclose the second UNION that is not using ALL. The second UNION is processed first because it is in parentheses, and returns 5 rows because the ALL option is not used and the duplicates are removed. These 5 rows are combined with the results of the first SELECT by using the UNION ALL keywords. This does not remove the duplicates between the two sets of 5 rows. The final result has 10 rows.
USE AdventureWorks2008R2;
GO
IF OBJECT_ID ('dbo.EmployeeOne', 'U') IS NOT NULL
DROP TABLE dbo.EmployeeOne;
GO
IF OBJECT_ID ('dbo.EmployeeTwo', 'U') IS NOT NULL
DROP TABLE dbo.EmployeeTwo;
GO
IF OBJECT_ID ('dbo.EmployeeThree', 'U') IS NOT NULL
DROP TABLE dbo.EmployeeThree;
GO
SELECT pp.LastName, pp.FirstName, e.JobTitle
INTO dbo.EmployeeOne
FROM Person.Person AS pp JOIN HumanResources.Employee AS e
ON e.BusinessEntityID = pp.BusinessEntityID
WHERE LastName = 'Johnson';
GO
SELECT pp.LastName, pp.FirstName, e.JobTitle
INTO dbo.EmployeeTwo
FROM Person.Person AS pp JOIN HumanResources.Employee AS e
ON e.BusinessEntityID = pp.BusinessEntityID
WHERE LastName = 'Johnson';
GO
SELECT pp.LastName, pp.FirstName, e.JobTitle
INTO dbo.EmployeeThree
FROM Person.Person AS pp JOIN HumanResources.Employee AS e
ON e.BusinessEntityID = pp.BusinessEntityID
WHERE LastName = 'Johnson';
GO
-- Union ALL
SELECT LastName, FirstName, JobTitle
FROM dbo.EmployeeOne
UNION ALL
SELECT LastName, FirstName ,JobTitle
FROM dbo.EmployeeTwo
UNION ALL
SELECT LastName, FirstName,JobTitle
FROM dbo.EmployeeThree;
GO
SELECT LastName, FirstName,JobTitle
FROM dbo.EmployeeOne
UNION
SELECT LastName, FirstName, JobTitle
FROM dbo.EmployeeTwo
UNION
SELECT LastName, FirstName, JobTitle
FROM dbo.EmployeeThree;
GO
SELECT LastName, FirstName,JobTitle
FROM dbo.EmployeeOne
UNION ALL
(
SELECT LastName, FirstName, JobTitle
FROM dbo.EmployeeTwo
UNION
SELECT LastName, FirstName, JobTitle
FROM dbo.EmployeeThree
);
GO
