I have a table of 5 columns. The first three are together unique, so they could be the primary key. Or, I could create an auto incrementing id column as the PK.
My question is - would it be faster to make a query on the three column PK, or on the single ID column PK? And how would that 3 column query look - like this...?
SELECT * FROM mytable WHERE col1 = 'blah' AND col2 = 'blahblah' AND col3 = 'blahblahblah'
I ask, as I see a lot of posts around saying 'why'd you make a new id column when you could use the unique columns as the PK?'
The other thing is, I'll be referencing rows in this table from other tables, so I'm thinking it's better so have an id column that I can refer to in the other tables.