Does the number of columns returned affect the speed of a query?

Question

If I have two queries

SELECT Id, Forename, Surname
FROM Person
WHERE PersonName Like(‘%frank%’)

And

SELECT *
FROM Person
WH         


        

Answer 1

Regardless of performance issues, it is good practice to always enumerate all fields in your queries.

• What if you decide to add a TEXT or BLOB column in the future that is used for a particular query? Your SELECT * will return the additional data whether you need it or not.
• What if you rename a column? Your SELECT * will always work, but the relying code will be broken.