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Tip of the Day
Language: SQL Server
Expertise: Beginner
Jul 20, 1999



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Using a SQL Function to Return a Column Number

Is it possible to return a number in a column, using a function, for each row in my result set? For example:
"Select RowNum As Rw, Fname, Birth From Employee." 
I am using Visual Basic 6.0.

What you require is possible, and there are a couple of ways for you to do it.

Most RDBMSs have a sequential number generator. In MS SQL the number generator is called the Identity property, which is not really a function, but a datatype.

The first thing you'll need to take advantage of this built-in function is a column created in your table with the identity property set. Do this in the CREATE statement of the table you're working on—to the effect of:

create table mytable (mycountingcolumn int identity(1,1))
insert mytable default values
select * from mytable
You should see a one-column table with a 1 in the first row.

If you already have a table set up and want to number the rows after the fact, you can create a mirror image of your table. Include the identity column definition and select into the new table. The identity column will fill itself up according to the starting point and increment you specified in the CREATE or ALTER TABLE statements.

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