SQL Server Performance

Cast Vs Convert

Discussion in 'General Developer Questions' started by Madhivanan, Jun 13, 2005.

  1. Madhivanan Moderator

    Is there any significant difference between these?
    From BOL
    quote:
    Explicitly converts an expression of one data type to another. CAST and CONVERT provide similar functionality.
    Why do SQL Server have two functions? Is any one of them not supported in earlier versions?




    Madhivanan

    Failing to plan is Planning to fail
  2. satya Moderator

    As stated in BOL they provide same functionality.

    Both translate a value from one data type to another. Although their performance is also similar, their syntax and potential usage is slightly different.

    For example, suppose that we want to retrieve order dates from the sales table. However, we don't care about the time portion; all we need to know is the order date. We could use either CAST or CONVERT to do this.

    Satya SKJ
    Moderator
    http://www.SQL-Server-Performance.Com/forum
    This posting is provided “AS IS” with no rights for the sake of knowledge sharing.
  3. dineshasanka Moderator

  4. Madhivanan Moderator

    That one is interesting discussion.
    I prefer to use convert specifically to format the dates and currency data types


    Madhivanan

    Failing to plan is Planning to fail
  5. FrankKalis Moderator

    Use CAST whenever you can. This is part of the SQL 92 standard. CONVERT might not be supported in future versions.

    --
    Frank Kalis
    Microsoft SQL Server MVP
    http://www.insidesql.de
    Ich unterstütze PASS Deutschland e.V. http://www.sqlpass.de)
  6. dineshasanka Moderator

    quote:Originally posted by FrankKalis

    Use CAST whenever you can. This is part of the SQL 92 standard. CONVERT might not be supported in future versions.

    any reasons for dropping CONVERT in future versions
  7. FrankKalis Moderator

    I guess the only reason might be, that it doesn't conform to the standard. And the standard offers with CAST an almost same functionality. Except for this date formatting. But this is more speculation than anything else.

    --
    Frank Kalis
    Microsoft SQL Server MVP
    http://www.insidesql.de
    Ich unterstütze PASS Deutschland e.V. http://www.sqlpass.de)

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