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Difference between COUNT(*) and COUNT(1)

  • June 24, 2002 at 9:04 am

    #78690

    OK silly question but waht is the performance differnec between COUNT(*) and COUNT(1) if any and why

    I have found it is possible to please all of the people all of the time if you do exactly what they want. Harold Macmillan 1961


    I have found it is possible to please all of the people all of the time if you do exactly what they want. Harold Macmillan 1961

  • June 24, 2002 at 9:45 am

    #431473

    I've never seen a difference documented for SQL Server. In Oracle count(1) is much faster because count(*) enumerates all the columns in a table before counting the rows. It is possible that SQL Server has the same preprocessor column enumeration with count(*) and not with count(1).

    I try to use count(1) as a best practice.

    DanW

  • June 25, 2002 at 1:20 am

    #431540

    Thanks Dan. that's waht I thought, to be honest I've not noticed any performance gain using count(1) in SQLSERVER. I've seen a gain using the ROWS column from SYSINDEXES, but it can often give slightly different results

    I have found it is possible to please all of the people all of the time if you do exactly what they want. Harold Macmillan 1961


    I have found it is possible to please all of the people all of the time if you do exactly what they want. Harold Macmillan 1961

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