Question

Re,

I have two tables. I would like to run a SELECT query where I would select table1.* and a “virtual” columnX that will return:

• YES table1.columnB = table2.columnB
• NO if no match is found in table2

Thanks in advance.

Answer 1

SELECT 
   t1.*,
   (CASE WHEN t2.columnB IS NOT NULL THEN 'YES' ELSE 'NO' END) as columnX
FROM
   table1 t1
   LEFT OUTER JOIN
   table2 t2
     ON  t1.columnB = t2.columnB