Question

Assuming I have two SQL tables consisting of a single column,

i.e.

Table 1               Table 2
a1                    a2
b1                    b2
c1                    c2

Is there a succinct SQL command to compare each record in one table against each record in the other? (and return true if any record from table 1 matches any record from table 2)

i.e.

if( a1 = a2 OR a1 = b2 OR a1 = c2 OR b1 = a2 OR b1 = b2…)

I want

If any record from table a matches table b (i.e., in a table of ints, they are the same int), return true.

Answer 1

Why not simply

if exists (select 1 from T1 inner join TB on T1.Col = T2.Col)