Question

I have got two tables say tableA and tableB. Both tables have fileds say pointA and pointB. I need a single query to find the highest and lowest value among the columns pointA and pointB.

 tableA
 idA    pointA
 1        20
 2        12
 3        41
 4        8     


 tableB
 idB    pointB
 1        24
 2        74
 3        2
 4        16    

I want to get the result like this

 HIGHEST     LOWEST
    74         2      

Answer 1

Try:

SELECT MAX(point) as HIGHEST, MIN(point) as LOWEST
FROM
  (SELECT pointA as point FROM tableA
   UNION
   SELECT pointB as point FROM tableB) t