I have table t2 with one index on column x and its unique index,
if suppose i want to create an another index on column y .. is it preferable to create composite index key ie. x+y key
or shall create another index for y column ?
this is related to the performance of query and the query is like this.
t1 a, t2 b
a.f1 = b.x and
b.y = 'joe pinto'