Question

I have table that has the following schema:

ID,firstName,MiddleName,LastName,FML,[some other columns]

FML column is created by concatenation firstName,space character,MiddleName,space character and last name. I want to search persong when you know FML. Therefore my query is

SELECT * from tbl where FML LIKE @Param

But I want to optimize this query, I’m thinking of separating input string into firstName,MiddleName,LastName strings and make query like that

SELECT * FROM tbl where firstName like @FN and MiddleName like @MN and LastName like @ln. 

Also will query

SELECT smth from tbl where Val='test'

Be better in terms of performance then

Select smth from tbl where Val like 'test'

Thank you.

Answer 1

If you mean =, then use =. If you mean like, then use like. But once you add wildcards to like, the performance will decrease.

By separating and filtering on separate fields, you lose flexibility, but increase the ability to be more specific in your search. So it’s not optimising, per se, as the functionality is different.

Imagine you have two records, Jack Roberts, and Robert Jack

Your first query allows you to find them both if your query is ‘%Robert%’, whereas the second allows you to find them with separate queries.