根据列选择不同的行

Question

A particular query of mine results data this way.

 Id    Size  
 123     1
 123     1
 123     2
 123     2
 134     1
 134     1
 134     2

I want the results get me the count eliminating the duplicate size like

 Id    Size  
 123     1
 123     2
 134     1
 134     2

Above was result of joining two tables. Problem is I cant use distinct in this case.

Here is how tables are

Table1:
   Id Created ... .. .. ..
   123 date1 ....
   134 date2 ....

Table2:     
 Id    Size  
 123     1
 123     2
 134     1
 134     2

I have my query that select from Table1 based on CreatedDate, its like this

 select count(*)
 from table1

 join table2
 on table1.id = table2.id

 where table1.creates between '' and ''.

How do you get the distinct sizes.

If I use select count(distinct table2.size), it only returns 1 and 2 for all rows.

Answer 1

SELECT DISTINCT Id, Size
    FROM table1

This should give you a list of distinct Id and Size combinations.

Answer 2

 select count(distinct table1.id, table2.size)
 from table1

 join table2
 on table1.id = table2.id

 where table1.creates between '' and ''

• see it working live in an sqlfiddle

Sometimes the solution is so obvious... :)

UPDATE: another way

select count(*) from (
     select distinct table1.id, table2.size
     from table1

     join table2
     on table1.id = table2.id

     where table1.creates between '' and ''
) sq