SQL Query to pivot and combine rows

Question

I have a table from which I need to derive results as shown below.

so far I am able to pivot F1 and combine currentvalue & mismatchcount using below sql.

SELECT object, GROUP_CONCAT(currentvalue  ,"-", mismatchcount ) as F1
FROM tableT  where freq = F1
GROUP BY object

but I need all three freq beside each other as output.

Answer 1

You could use this query:

SELECT   object, 
         GROUP_CONCAT(CASE freq WHEN 'F1' THEN
                         CONCAT(currentvalue, "-", mismatchcount) END SEPARATOR " ") as F1,
         GROUP_CONCAT(CASE freq WHEN 'F2' THEN
                         CONCAT(currentvalue, "-", mismatchcount) END SEPARATOR " ") as F2,
         GROUP_CONCAT(CASE freq WHEN 'F3' THEN
                         CONCAT(currentvalue, "-", mismatchcount) END SEPARATOR " ") as F3
FROM     tableT 
GROUP BY object

The CONCAT function is used to concatenate values from the same record, GROUP_CONCAT is used to concatenate such values from different records. The CASE WHEN expression is evaluated for several records (with different values for freq ) and thus returns several values. But of those values the non-null values need to concatenated. The separator is set to the space.