group by

mcalpine

what actually happens when i use two or more columns in the GROUP BY clause of an SQL statement?

-m

tomhath

The result set will contain a single row for each distinct set of values from the columns that are grouped. For example, if you group by columns x and y, you should get three rows back (a,m,1), (b,m,2), and (b,n,1). The SELECT and GROUP BY should always contain the same list of columns.

select x, y, count(*) from mytab group by x, y

x   y
-   -
a   m 
b   m
b   n
b   m

mcalpine

then would i need to use another php method to get the results out or do they come out as one set of results?

when i try using many groups and executing the statement in PHPMYADMIN , i get same results..... whether i use one group column or two....

please explain further....

thanks
-m

tomhath

Post the queries you are running. I'm not sure what you mean by "one set of results"; a select statement will always return one result set (one set of rows)