How to ALTER multiple columns at once in SQL Server

sql-server tsql alter-column
D.mahesh picture D.mahesh · Aug 12, 2010 · Viewed 287.1k times · Source

I need to ALTER the data types of several columns in a table.

For a single column, the following works fine:

ALTER TABLE tblcommodityOHLC
ALTER COLUMN
    CC_CommodityContractID NUMERIC(18,0)

But how do I alter multiple columns in one statement? The following does not work:

ALTER TABLE tblcommodityOHLC
ALTER COLUMN
    CC_CommodityContractID NUMERIC(18,0), 
    CM_CommodityID NUMERIC(18,0)

Answer

Neil Knight picture Neil Knight · Aug 12, 2010

This is not possible. You will need to do this one by one. You could:

  1. Create a Temporary Table with your modified columns in
  2. Copy the data across
  3. Drop your original table (Double check before!)
  4. Rename your Temporary Table to your original name

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