CODEWITHSUNDEEP
mysql
user1311286
user1311286

Reputation:

My SQL. Finding multiples in a single column

Relations: Product(maker, model, type) Laptop(Model, price, speed, ram, hd, screen) PC(model, price, speed, ram, hd) Printer(model,price, color, price)

I am trying to find pc's who share HD sizes with one another. So basically finding out the model number of pc's who share a HD size with another pc.

What I have tried:

SELECT DISTINCT hd FROM pc;

Which gives me all of the HD sizes. I am not sure how I would go about figuring out if those numbers occur twice in a relation.

I figure it is something along the lines of

SELECT DISTINCT hd FROM pc WHERE hd IN (SELECT hd FROM pc);

But I am not sure how to say " IN MULTIPLE TIMES" ?

Upvotes: 1

Views: 74

Answers (1)

Michael Fredrickson
Michael Fredrickson

Reputation: 37398

You can use the GROUP BY and HAVING clauses to accomplish this:

SELECT hd, COUNT(*) AS occurrences
FROM pc
GROUP BY hd
HAVING COUNT(*) > 1

Upvotes: 1

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