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Set/Select Statement RRS feed

  • Question

  • User-797751191 posted

    Hi

      Wht is the difference between below 2 statements

    select @Dr_Cr = 'Cr'
    
    Set @Cr_Trans = @Cr_Opg;

    When we have to give ; & when ,

    Thanks

    Saturday, November 16, 2019 4:09 PM

Answers

  • User288213138 posted

    Hi jsshivalik,

    When we have to give ; & when ,

    Can you tell me what this sentence means?

    select @Dr_Cr = 'Cr'
    
    Set @Cr_Trans = @Cr_Opg

    Do you mean you want to know the difference between select and set?

    if so, you can refer to this link: https://stackoverflow.com/a/3945396

    1. SET is the ANSI standard for variable assignment, SELECT is not.
    2. SET can only assign one variable at a time, SELECT can make multiple assignments at once.
    3. If assigning from a query, SET can only assign a scalar value. If the query returns multiple values/rows then SET will raise an error. SELECT will assign one of the values to the variable and hide the fact that multiple values were returned (so you'd likely never know why something was going wrong elsewhere - have fun troubleshooting that one)
    4. When assigning from a query if there is no value returned then SET will assign NULL, where SELECT will not make the assignment at all (so the variable will not be changed from its previous value)
    5. As far as speed differences - there are no direct differences between SET and SELECT. However SELECT's ability to make multiple assignments in one shot does give it a slight speed advantage over SET.

    If I misunderstand your requirement, please post more details information about your requirement.

    Best regards,

    sam

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Monday, November 18, 2019 7:09 AM