CODEWITHSUNDEEP
mysqlsqljoin
Joshua H.
Joshua H.

Reputation: 87

SQL Left Join does not show all rows

I have the following Query:

At the moment i get the following code:

It gives back only one tag not the three tags in the database.

The database looks like this:

In this Database are 3 tags with bm_tagslang = 'de' but i only get one.

Does someone know what i am doing wrong?

Upvotes: 0

Views: 43

Answers (1)

Gordon Linoff
Gordon Linoff

Reputation: 1269633

Move tagslang.lang into the on condition. When there is no match, it is NULL, so it changes the left join to an inner join:

on blog.id = tagslang.blogid and tagslang.lang = ?

You also need to change the group by. It should be:

group by blog.id

Otherwise, you may be grouping by a NULL value.

As a note: Do not use columns in the group by that are not in the SELECT. This is a MySQL (mis)feature that should not be used unless you really understand what you are doing.

Upvotes: 1

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