Converting Data

  • Hi,

    This is probably a simple one for someone with more experience than me but it's got me stumped.

    We have a table which holds values of different types but just stored as varchars i.e.

    CREATE TABLE tbl_values2 (

    value_id int IDENTITY (1, 1) NOT NULL ,

    value_label varchar(255) NOT NULL,

    value varchar (255) NOT NULL)

    INSERT INTO tbl_values2 (value_label, value)

    SELECT 'HBA1c','7'

    UNION SELECT 'HBA1c Date', '01-01-2009 00:00:00.000'

    UNION SELECT 'HBA1c','ABC'

    UNION SELECT 'HBA1c Date', '10-01-2009 00:00:00.000'

    The problem we have is that the app that is used to populate the data lets you enter any free text into the value as it is not validated. (I know poor design on both the app and db).

    What we want to do for example is get a list of all HBA1c's and display them as a decimal value. But as in this example one is ABC and not a number it fails to convert it to an decimal thus the query fails.

    SELECT CONVERT(decimal(5,2),value) from tbl_values

    WHERE value_label = 'HBA1c'

    Which gives the error:

    Server: Msg 8114, Level 16, State 5, Line 1

    Error converting data type varchar to numeric.

    Is there anyway I can get it to just return the successfully converted row and ignore the one that fails?

    Cheers

    R

    MCITP SQL 2005, MCSA SQL 2012

  • While not perfect try using the IsNumeric Function, check out the BOL Entry for it. So your query could be this:

    SELECT

    CONVERT(decimal(5,2),value)

    from

    tbl_values

    WHERE

    value_label = 'HBA1c' And

    IsNumeric(value) = 1

    You may still get some errors which is why I mention reading the BOL Entry for IsNumeric.

  • What we want to do for example is get a list of all HBA1c's and display them as a decimal value. But as in this example one is ABC and not a number it fails to convert it to an decimal thus the query fails.

    Which way you intend to display 'ABC' as a decimal value?

    _____________
    Code for TallyGenerator

  • Jack, thanks for this will give it a try. Is there a ISDATE as we have the same problem for dates as well?

    MCITP SQL 2005, MCSA SQL 2012

  • Yes there is an IsDate function as well.

  • Cracked it, thanks for the help.

    MCITP SQL 2005, MCSA SQL 2012

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