Question

I currently have the following query

SELECT table1.col1, table2.col2  
FROM   table1     
    INNER JOIN table2 ON table1.col1=table2.col6  
WHERE  col3 IN 
           (SELECT col1 
            FROM table3 
            WHERE col4 IN (
                   SELECT col4 
                   FROM table4 
                   WHERE col5 LIKE '%XYZ%'
               )       
            )  ORDER BY table1.col1 

The Result I get is as follows

COL1  |  COL2
Bob      LA
BOB      NY
Charlie  SF
Donald   Phoenix
Edward   Chicago
Edward   DC
Florence Miami
George   Sunnyvale
Helen    Orlando
Helen    Houston

If you observe the results, the following entries are duplicated on Col1 (Bob, Edward, Helen). The following are only single records(Charlie, Donald, Florence, George).

What I want are 2 different queries where one query should return only the single records and another query should return only the duplicates. “I need BOTH Col1 and Col2 returned from both the queries”. I have tried to modify, but either it gives an error or it does not result in any reults .

Desired result

Query1 result (Only single records)

COL1  |  COL2
Charlie  SF
Donald   Phoenix
Florence Miami
George   Sunnyvale

Query2 result (Only duplicate records returned)

COL1  |  COL2
Bob      LA
BOB      NY
Edward   Chicago
Edward   DC
Helen    Orlando
Helen    Houston

Answer 1

And if it isn’t Oracle, get familiar with the GROUP BY xxx HAVING yyy = z construct.

Simply adding it to your query won’t work because you want to select also a column you are not grouping by, but here is one simple way of eating your cake and having it:

SELECT table1.col1, table2.col2  
FROM   table1     
INNER JOIN table2 ON table1.col1=table2.col6  
WHERE  col3 IN 
       (SELECT col1 
        FROM table3 
        WHERE col4 IN (
               SELECT col4 
               FROM table4 
               WHERE col5 LIKE '%XYZ%'
           )       
        )
AND col1 IN (
    SELECT table1.col1
    FROM   table1     
        INNER JOIN table2 ON table1.col1=table2.col6  
    WHERE  col3 IN 
       (SELECT col1 
        FROM table3 
        WHERE col4 IN (
               SELECT col4 
               FROM table4 
               WHERE col5 LIKE '%XYZ%'
           )       
        )
    GROUP BY table1.col1
    HAVING COUNT(table1.col1) > 1
)
ORDER BY table1.col1