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Posted by gelangov on 07/23/07 15:00
create table table1
(field1 varchar (8),
field2 varchar (4))
field1 and field2 together is unique.
Example data:
Field1 Field2
1 A
1 B
1 C
2 A
2 C
3 A
3 B
3 D
4 A
4 B
1. The query one should find all the Field1 that has Field2 value of
ONLY (A) and (B)
Here the result will be Field1, 4 (only one result)
2. The query two should find all the Field1 that has Field2 value of
(A)and (B)
Here the result will be Field1,1,3 and 4 (three results)
Right now, I am doing this way...Is there a more efficient way than
this?
-- Query one:
SELECT <a.field1> from
(SELECT <field1>, <field2> FROM table1
WHERE <field2> ='A'
UNION
SELECT <field1>, <field2> FROM table1
WHERE <field2> ='B'
UNION
SELECT <field1>, <field2> FROM table1
WHERE <field2> ='C') a
WHERE <a.field1> not in (SELECT <field1>
FROM table1 WHERE <field2> not in ('a', 'b', 'c'))
GROUP by <a.field1>
HAVING count(*) =3
order by <a.field1>
--query 2
SELECT <a.field1> from
(SELECT <field1>, <field2> FROM table1
WHERE <field2> ='a'
UNION
SELECT <field1>, <field2> FROM table1
WHERE <field2> ='b'
UNION
SELECT <field1>, <field2> FROM table1
WHERE <field2> ='c'
)a
GROUP by <a.field1>
HAVING count(*) =3
order by <a.field1>
Thank you so much !!!
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