What is the reason not to use select *?

Question

I\'ve seen a number of people claim that you should specifically name each column you want in your select query.

Assuming I\'m going to use all of the columns anyway

Answer 1

Just to add one thing that no one else has mentioned. Select * returns all the columns, someone may add a column later that you don't necessarily want the users to be able to see such as who last updated the data or a timestamp or notes that only managers should see not all users, etc.

Further, when adding a column, the impact on existing code should be reviewed and considered to see if changes are needed based on what information is stored in the column. By using select *, that review will often be skipped because the developer will assume that nothing will break. And in fact nothing may explicitly appear to break but queries may now start returning the wrong thing. Just because nothing explicitly breaks, doesn't mean that there should not have been changes to the queries.