Sql server® 2012 t-sql fundamentals

The 

LIKE

 predicate

T-SQL provides a predicate called LIKE that allows you to check whether a character string matches a 

specified pattern. Similar patterns are used by the PATINDEX function described earlier. The following 

section describes the wildcards supported in the patterns and demonstrates their use.

The 

%

 (percent) Wildcard

The percent sign represents a string of any size, including an empty string. For example, the following 

query returns employees where the last name starts with D.

SELECT empid, lastname 

FROM HR.Employees 

WHERE lastname LIKE N'D%';

This query returns the following output.

empid       lastname 

----------- -------------------- 

1           Davis 

9           Dolgopyatova

Note that often you can use functions such as SUBSTRING and LEFT instead of the LIKE predicate 

to represent the same meaning. But the LIKE predicate tends to get optimized better—especially 

when the pattern starts with a known prefix.

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Microsoft SQL Server 2012 T-SQL Fundamentals