Question

I have 4 SQL queries that fetch data from the same table and I was wondering whether you can create a view containing multiple queries. For instance, one of these queries looks something like:

SELECT Count(COLUMN1) FROM TABLE1 WHERE COLUMN3 > '01-Oct-12' AND COLUMN3< '01-Nov-12' 

whereas another looks like:

SELECT Count(COLUMN2) FROM TABLE1 WHERE COLUMN3 > '01-Oct-12' AND COLUMN3 < '01-Nov-12' 

Thanks,

I.

Answer 1

The simplest implementation would be:

create or replace view v23 as 
     select count(column1) as col1_count
            , count(column2) as col2_count
     from TABLE1
      WHERE COLUMN3 > '01-Oct-12' AND COLUMN3 < '01-Nov-12' 

But if not all your queries use the same criteria you could use scalar sub-queries:

create or replace view v23 as 
  select 
     (select count(column1) from TABLE1 
        WHERE COLUMN3 > '01-Oct-12' AND COLUMN3 < '01-Nov-12' ) as col1_count 
     , (select count(column2) from TABLE2 
        WHERE COLUMN3 > '01-Oct-12' AND COLUMN3 < '01-Nov-12' ) as col2_count
  from dual