SQL query to select e.g. buyer which made 3 specific buys - sql

Question

I have a table like this:
ToyStore
+----+------------+-------------------+
| ID | NAME | PURCHASE |
+----+------------+-------------------+
| 1 | Ramesh | Teddy bear |
| 2 | Khilan | Drum |
| 3 | Chaitali | Chess |
| 4 | Hardik | Wooden sword |
|... | ... | ... |
+----+------------+-------------------+
I need to select all the buyers which have made all 3 purchases - Teddy bear, Chess and Wooden sword and their purchases
As a result there should be something like this:
+--------+-------------------+
| NAME | PURCHASE |
+--------+-------------------+
| Ramesh | Teddy bear |
| Ramesh | Chess |
| Ramesh | Wooden sword |
| Khilan | Teddy bear |
| Khilan | Chess |
| Khilan | Wooden sword |
+--------+-------------------+
Thanks in advance

Answer 1

select * from ToyStore ts1 where
exists (select 1 from ToyStore ts2 where
ts1.name=ts2.name and purchase ='Teddy bear')
and
exists (select 1 from ToyStore ts2 where
ts1.name=ts2.name and purchase ='Chess')
and
exists (select 1 from ToyStore ts2 where
ts1.name=ts2.name and purchase ='Wooden sword')

Answer 2

If you want to find all names with exact one row of each matching toy and only These three rows you could use the following query:
(of course there are smarter ways, but this is very easy to understand and to Change)
With
-- Data
TOYSTORE AS (
SELECT 1 ID, 'Ramish' NAME, 'Teddy Bear' PURCHASE FROM DUAL UNION ALL
SELECT 2, 'Khilan', 'Drum' FROM DUAL UNION ALL
SELECT 3, 'Chaitali', 'Chess' FROM DUAL UNION ALL
SELECT 4, 'Hardik', 'Wooden sword' FROM DUAL UNION ALL
SELECT 5, 'Hardik', 'Chess' FROM DUAL UNION ALL
SELECT 6, 'Hardik', 'Teddy Bear' FROM DUAL UNION ALL
SELECT 7, 'Chaitali', 'Chess' FROM DUAL UNION ALL
SELECT 8, 'Chaitali', 'Wooden sword' FROM DUAL UNION ALL
SELECT 9, 'Chaitali', 'Teddy Bear' FROM DUAL UNION ALL
SELECT 10, 'Khilan', 'Chess' FROM DUAL UNION ALL
SELECT 11, 'Khilan', 'Wooden sword' FROM DUAL UNION ALL
SELECT 12, 'Khilan', 'Teddy Bear' FROM DUAL
),
-- Matching items
MyMatches AS (
SELECT 'Teddy Bear' PURCHASE FROM DUAL UNION ALL
SELECT 'Chess' FROM DUAL UNION ALL
SELECT 'Wooden sword' FROM DUAL
),
-- all single hits of matching items
MyStrikes AS (
SELECT NAME, PURCHASE, COUNT(*) CNT
FROM TOYSTORE
NATURAL JOIN MyMatches
GROUP BY NAME, PURCHASE
HAVING COUNT(*) = 1
),
-- all names with exactly one item of each kind
My3Strikes AS (
SELECT NAME, SUM(CNT) CNT
FROM MyStrikes
GROUP BY NAME
HAVING SUM(CNT) = 3
),
-- number of all not matching items
MyBlanks AS (
SELECT NAME, COUNT(PURCHASE) CNT --COUNT(PURCHASE) CNT
FROM TOYSTORE
WHERE NOT PURCHASE IN ('Teddy Bear', 'Chess', 'Wooden sword')
GROUP BY NAME
),
-- all names
MyNames AS (
SELECT D.NAME
FROM TOYSTORE D
GROUP BY D.NAME
)
-- the result
SELECT D.NAME
FROM MyNames D
JOIN My3Strikes S ON S.Name = D.Name
LEFT JOIN MyBlanks B ON B.Name = D.Name
WHERE B.CNT IS NULL
;

Answer 3

There are some things not completely clear for me. Do you want to know, whether any 3 items are in list? If so, the next query would help.
SELECT NAME, COUNT(PURCHASE)
FROM TOYSTORE
GROUP BY NAME
HAVING COUNT(PURCHASE) = 3
gives all names, that have exactly 3 items in his list.
This query you need for an inner join:
SELECT T.NAME, T.PURCHASE
FROM TOYSTORE T
JOIN (
SELECT NAME, COUNT(PURCHASE)
FROM TOYSTORE
GROUP BY NAME
HAVING COUNT(PURCHASE) = 3
) I
ON I.NAME = T.NAME
Does this solve your Problem?
If not, tell us more.
Questions may be:
What, if someone buys 2 teddybears and 1 sword?
What, if someone buys all three items and another more item?