Question

I’m trying to update all SQL rows in the [Temp_LTGData] table setting the [CORP_REG_NO] value to the value in another row in the same table where the [CUSTOMER_NUMBER] matches.

Ultimately I need to do this with quite a few columns, does anyone know if this can be done?

I can’t seem to use the LTGSource alias like in a select query 🙁

 Update [MandS].[dbo].[Temp_LTGData] LTGSource
    Set [CORP_REG_NO] = (SELECT [CORP_REG_NO] 
                           FROM [MandS].[dbo].[Temp_LTGData] 
                          WHERE ([CORP_REG_NO] IS NULL 
                            AND [CUSTOMER_NUMBER] = LTGSource.[CUSTOMER_NUMBER] ))
  where [CORP_REG_NO] IS NULL

Thanks for the feedback guys that’s some really awesome stuff, I even learnt some different approaches to this problem (voted for you all).

Answer 1

Try the following to get exactly what you were doing

UDPATE [MandS].[dbo].[Temp_LTGData] LTGSource 
SET [CORP_REG_NO] = (SELECT [CORP_REG_NO] 
                     FROM [MandS].[dbo].[Temp_LTGData] 
                     WHERE ([CORP_REG_NO] IS NULL 
                          AND [CUSTOMER_NUMBER] = ToUpdate.[CUSTOMER_NUMBER] )) 
FROM {MandS].[dbo].[Temp_LTGData] ToUpdate
where [CORP_REG_NO] IS NULL

However, you have a mistake in your query I believe the subquery should be IS NOT NULL.