SQL BIT Data Type

Use the SQL BIT data type to define columns, variables, and parameters value of 1, 0, or NULL. 

Given their Yes/No nature, designer us the BIT type with flag and indicator columns: 

Converting BIT Values 

The string values TRUE and FALSE convert to BIT:  TRUE is converted to 1 and FALSE to 0. 

Converting any non-zero value promotes BIT to 1. 

Examples

Here is SQL to query all employees receiving a salary: 

SELECT NationalIDNumber 
 , JobTitle 
 , SalariedFlag 
FROM HumanResources.Employee 
WHERE SalariedFlag = 1;

Additional Resources 

To learn more about data types, check out these useful resources: 

• Common Data Types used in SQL Server 
• How do I handle a “Error converting data type” error? 
• Recommended book – SQL Queries for Mere Mortals