I was wondering if is more memory-efficient to include LIMIT 1 on queries
when we expect 1 result at all times.
So for example I have the following query
select * from clients where client_id = x
I don't have extensive db management skills but I'm assuming that
select * from clients where client_id = x limit 1
would be a bit more memory efficient because the query
wont have to iterate thru each row on the table once it finds
Am I right or it doesn't matter if I include limit in this specific case?
Best How To :
It could make a big difference if you do not have an index.
Consider the following with no index:
where client_id = x
The engine will need to scan the entire table to determine that there is only one row. With
limit 1 it could stop at the first match.
However, if you have an index, then the index would have the information for equality comparisons. So, the limit would not make a difference in terms of performance. There might be some slight difference, but it should be negligible.