Counting number of grouped rows in mysql
Try this simple query without a sub-query:
SELECT COUNT(DISTINCT component) AS TotalRowsFROM xyzWHERE labref = 'NDQA201303001';See this SQLFiddle
I found the solution.So, if you want to count quantity of groups, not quantity of elements in each group, and return duplicate value to every group record in result table, you should use OVER() clause on you'r count function.
So, for example above the solution would be
SELECT component, COUNT(*) OVER() as number_of_components FROM `xyz` WHERE labref = 'NDQA201303001' GROUP BY componentI suppose that works with any query that use GROUP BY, additional info, check in the link above.