Question
Background Information
Ordinal position notation, AKA ordinals, is column shorthand based on the
column order in the list of columns in the SELECT clause, instead of either
the column name or column alias. Commonly supported in the ORDER BY clause,
some databases (MySQL 3.23+, PostgreSQL 8.0+) support the syntax for the
GROUP BY clause as well.
Here's an example of using Ordinals:
GROUP BY 1, 2
ORDER BY 1, 2
It's not good to use because it makes the query brittle - if the column order
changes, the ordinals need to be updated or your query won't return what you
thought it would. Very likely, you'd get an error when used in the GROUP BY
if the columns at those locations are wrapped within aggregates...
The Question
The only benefit I can think of is less data to send over the wire, if you aren't using stored procedures or functions (which make ordinal usage moot, to me anyways). Are there any other benefits I'm missing?
Answer
I'd use it:
- If you love troubleshooting
- Creating adhoc queries without intellisense
There is no upside.
SQL Server only supports in the ORDER BY anyway. Anywhere else it's an expression to be evaluated.
