MySQL: one or more rows?

Question

I have any type of content that now has an identifier. I can specify several typesfor the content.

The question is should I use multiple lines to add multiple types or use a field typeand put the types there, separated by commas, and parse them intoPHP

A few lines

`content_id` | `type`

1            | 1
1            | 2
1            | 3

VS

Single line

`content_id` | `type`

1            | 1,2,3

EDIT

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I am looking for a quick answer, but not easier, think about it. Performance is really important to me. So I'm talking about a really huge database with millionsor strings ten millions.

Answer 1

" ", :

• SQL , , WHERE type=3 , WHERE type LIKE '%3%',
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Answer 2

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Answer 3

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Answer 4

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:

http://www.databasedesign-resource.com/denormalization.html

Answer 5

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Answer 6

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If there is some trivial gain, it is simply not worth it.