Choice problem

Question

I have a table with rows with two columns

A 1 A 2 B 1 B 3 C 1 C 2 C 3 

and I want to get from this only this identifier (a, b or c), which has only 2 rows with a value of 1.2, so from this table I should get a, bcause b does not have a row with 2 and c has rows with 1 and b, but also has a string with c ..

What is the easiest way to get this string?

Answer 1

 SELECT col1 FROM YourTable GROUP BY col1 HAVING COUNT(DISTINCT col2) =2 AND MIN(col2) = 1 AND MAX(col2) = 2 

Or another way, expandable by more than 2 numbers

 SELECT col1 FROM yourtable GROUP BY col1 HAVING MIN(CASE WHEN col2 IN ( 1, 2 ) THEN 1 ELSE 0 END) = 1 AND COUNT(DISTINCT col2) = 2 

Answer 2

 select t1.col1 from table as t1 left join table as t2 on (t1.col1 = t2.col1) where t1.col2 = 1 and t2.col2 = 2;