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COALESCE vs ISNULL

A good read. 

 Deciding between COALESCE and ISNULL in SQL Server (mssqltips.com)


Key Points : 

  • The COALESCE and ISNULL SQL Server statements handle data type precedence differently

COALESCE determines the type (and length) of the output based on data type precedence.   ISNULL takes the first parameter. 

  • The SQL Server COALESCE statement supports more than two arguments

  • COALESCE and ISNULL perform about the same (in most cases) in SQL Server
  • ISNULL is not consistent across Microsoft products/languages
  • COALESCE is ANSI standard




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