Question

I have a MySQL table from which I want to select:

1) Either “most occurring” value, if there is any prevailing

2) Or “average” value, if there is no most occurring value.

Example table 1:

value
1
2
3
4

All values are occurred equally, therefore I want to take AVG(`value`)

Example table 2:

value
1
2
2
3

Value 2 prevails, therefore I want to select the value 2.

What mysql query would do this?

Answer 1

Starting from Gordon’s answer I tested and corrected the SQL query in SQL Fiddle:

SELECT IF(t4.numcnts = 1, t1.avgvalue, t2.topvalue) AS result 
 FROM (select avg(value) as avgvalue from test) t1 
 CROSS JOIN (select value as topvalue from test group by value order by count(*) desc limit 1) t2 
 CROSS JOIN join (select count(distinct cnt) as numcnts from 
    (select count(*) as cnt from test group by value) t3) t4

Here is the Fiddle with the two test tables (switch out test2 for test to see the result when a particular value prevails): http://sqlfiddle.com/#!2/76914/3

My changes were to use an IF instead of a CASEstatement in the SELECTclause and to add the necessary table aliases for the subselects.