Making Query Coding in SQL Easier by Implementing the SQL Divide Keyword - Advanced Database Query Systems - page 296

FROM T1, T2
WHERE T1.a = T2.a AND T1.b > 0
Divisor: SELECT b, c
FROM T3, T4
WHERE T3.d = T4.d
On: b
Replacing
(SELECT a, b, c
FROM T1, T2
WHERE T1.a = T2.a AND T1.b > 0)
Divide
(SELECT b, c
FROM T3, T4
WHERE T3.d = T4.d) ON {b}
with
SELECT a, c
FROM T1, T2
WHERE ((T1.a = T2.a) AND (T1.b > 0)) AND b IN
(SELECT b, c
FROM T3, T4
WHERE (T3.d = T4.d))
GROUP BY a, c
HAVING COUNT(*) =
(SELECT COUNT(*)
FROM T3, T4
WHERE (T3.d = T4.d)).
The original query now looks like:
SELECT a, c
FROM T1, T2
WHERE ((T1.a = T2.a) AND (T1.b > 0)) AND b IN
(SELECT b, c
FROM T3, T4
WHERE (T3.d = T4.d))
GROUP BY a, c
HAVING COUNT(*) =
(SELECT COUNT(*)
FROM T3, T4
WHERE (T3.d = T4.d)))
DIVIDE
((SELECT a, d
FROM T1, T2
WHERE T1.a = T2.a AND T1.b < 0)
Divide
(SELECT d, c