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SQL Server FAQ - What Is a Boolean Value

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(Continued from previous topic...)

What Is a Boolean Value?

A Boolean value indicates a condition in a state of TRUE or FALSE. In Transact-SQL language, there is not storage data type defined to store a Boolean value. So Boolean values can only exist temporarily as part of the execution of Transact-SQL expression or statement.

Boolean values are returned from comparison operations. The tutorial exercise below shows you some examples of how Boolean values are used:

-- Boolean values in a CASE expression
SELECT CASE WHEN 1>0 THEN
      'True'
   ELSE
      'False'
   END;
GO
True

-- Boolean values in an IF statement
IF 1>0 
   SELECT 'True';
ELSE
   SELECT 'False';
GO
True

-- Stand alone Boolean value not allowed 
SELECT 1>0;
GO
Msg 102, Level 15, State 1, Line 1
Incorrect syntax near '>'.

(Continued on next topic...)

1. What Is a Boolean Value?
2. What Are Conditional Expressions?
3. What Are Comparison Operations?
4. How To Perform Comparison on Exact Numbers?
5. How To Perform Comparison on Floating Point Numbers?
6. How To Perform Comparison on Date and Time Values?
7. How To Perform Comparison on Character Strings?
8. What To Test Value Ranges with the BETWEEN Operator?
9. What To Test Value Lists with the IN Operator?
10. What To Perform Pattern Match with the LIKE Operator?
11. How To Use Wildcard Characters in LIKE Operations?
12. How To Test Subquery Results with the EXISTS Operator?
13. How To Test Values Returned by a Subquery with the IN Operator?
14. What Are Logical/Boolean Operations?