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Join two tables who both have a record

开发者 https://www.devze.com 2023-03-15 05:05 出处:网络
I need to join two tables with a shared ID, but I only want to return a row if both tables contain a row.I found a solution with sub-queries, but want to avoid them (because this query is run multiple

I need to join two tables with a shared ID, but I only want to return a row if both tables contain a row. I found a solution with sub-queries, but want to avoid them (because this query is run multiple times a page load).

An example:

`Products`:
Name    PicID
------|-------
Test1 |   4
Test2 |   5
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`Images`:
PicID   Picture
------|--------
   4  |  BLOB

A query would only return Test1 (with the blob) because Test2 doesn't have a row in the picture table.

Thoughts?

Max


An INNER JOIN is used to guarantee that the matching values exist in both tables.

SELECT p.PicID, p.Name, i.Picture
    FROM Products p
        INNER JOIN Images i
            ON p.PicID = i.PicID


SELECT P.Name, P.PicID, I.Picture
FROM Products P
INNER JOIN Images I
ON p.PicID = I.PicID


Select * 
FROM Products, Images
WHERE Product.PicID = Images.PicID
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