Question

i would like to know which one of these will execute faster and why:

select column1 from table1 where 1=1

or

select column1 from table1 where 1<=1

would there be a difference in performance between oracle/sql server/mysql?

please also consider where instead of 1, we use some variable x

what would be faster assuming x = 2

select column1 from table1 where x=2

or

select column1 from table1 where x<=2

if you do have more answers, since it’s closed, just add comments.

Answer 1

Well, those are nonsensical queries. But, in general, it’s impossible to answer this sort of question definitively without comparing the query plans. A database system will evaluate queries differently depending on any number of factors including the indexes that are available and the size of the tables.

If you’re using MySQL or PostgreSQL, you can get a query plan by adding EXPLAIN to the start of the query and running it in a terminal. See the MySQL documentation or PostgreSQL documentation for more information.