"group by is used to organize the data before other clauses - such as where, order by and functions...",really? Ref: Learning MySQLupdate

Question

"group by is used to organize the data before other clauses - such as where, order by and functions -are applied. In contrast, order by is applied last- after the query has been resolved -to reorganize the query output for display.",really? Ref: Learning MySQL

I have surfed the net regarding this but couldn't find anything like this. Is this an error in book?

update: I just notices alias works in group by which means it is getting executed after select, since select is executed after where , can we safely say that it was an error with the book and group by is executed after where clause?

What makes you think it is an error? give more context, you'll get better answers. — Mahn, Jul 16 '12 at 08:38
i have googled but nothing says group by is executed first ... is there a way to confirm this? — Sandy, Jul 16 '12 at 08:40

score 0 · Answer 1 · answered Jul 16 '12 at 08:11

0

Better explanation is here http://www.bennadel.com/blog/70-SQL-Query-Order-of-Operations.htm

answered Jul 16 '12 at 08:11

Madhivanan

13,470
1
24
29

thanks Madhivanan for the link but i am confused with this order because group by supports alias so it is definitely executed after select ( 1. FROM clause 2. WHERE clause 3. GROUP BY clause 4. HAVING clause 5. SELECT clause 6. ORDER BY clause ) – Sandy Jul 17 '12 at 05:06

"group by is used to organize the data before other clauses - such as where, order by and functions...",really? Ref: Learning MySQLupdate

1 Answers1