DATETIME SELECT SELECT INTO DATE PAD STRING DYNAMIC SQL CURSOR MONEY FORMAT PERCENT STORED PROCEDURE SQL SERVER AGENT JOB OPTIMIZATION WHILE LOOP OVER PARTITION BY UPDATE
 
 
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How to use UNION ALL instead of or?

The following Microsoft SQL Server T-SQL sample code demonstrates the use of UNION ALL. Index usage is usually better with UNION ALL:

--  T-SQL UNION ALL operator - duplicates are NOT eliminated

USE Northwind

GO

 

SELECT CompanyName,  -- 3 rows

       ContactName,

       ContactTitle,

       Phone

FROM   Customers

WHERE  Country = 'Canada'

UNION ALL

SELECT CompanyName,  -- 3 rows

       ContactName,

       ContactTitle,

       Phone

FROM   Customers

WHERE  Country = 'Canada'

UNION ALL

SELECT CompanyName,   -- 0 rows

       ContactName,

       ContactTitle,

       Phone

FROM   Customers

WHERE  Region = 'Quebec'

UNION ALL

SELECT CompanyName,  -- 0 rows

       ContactName,

       ContactTitle,

       Phone

FROM   Customers

WHERE  City = 'Montreal'

 

/*

CompanyName             ContactName       ContactTitle            Phone

Bottom-Dollar Markets   Elizabeth Lincoln Accounting Manager      (604) 555-4729

Laughing Bacchus Wine   Yoshi Tannamuri   Marketing Assistant     (604) 555-3392

Mère Paillarde          Jean Fresnière    Marketing Assistant     (514) 555-8054

Bottom-Dollar Markets   Elizabeth Lincoln Accounting Manager      (604) 555-4729

Laughing Bacchus Wine   Yoshi Tannamuri   Marketing Assistant     (604) 555-3392

Mère Paillarde          Jean Fresnière    Marketing Assistant     (514) 555-8054*/

 

Exam Prep 70-461
SQL 2016 DESIGN & PROGRAMMING
 
 
 
DATETIME SELECT SELECT INTO DATE PAD STRING DYNAMIC SQL CURSOR MONEY FORMAT PERCENT STORED PROCEDURE SQL SERVER AGENT JOB OPTIMIZATION WHILE LOOP OVER PARTITION BY UPDATE