MySQL通过id组合了两个表

I have two tables:

Table alpha

id  |  title  |  catid

1   |  winter |  105
2   |  summer |  105
3   |  fall   |  20
4   |  spring |  12

Table beta

id  |  author

1   |  john
2   |  mike
3   |  bill

Table result — I would like to generate the following table by matching the id from the two tables above. Using only those colums WHERE "catdid" is 105.

id  |  author |  title

1   |  john   |  winter
2   |  mike   |  summer

I have the following query:

$table_alpha = "alpha";
$table_beta = "beta";

$sql = "
SELECT id, title, catid, author 
FROM $table_alpha, $table_beta 
WHERE catid = 105
…
???
…
";

Any ideas? Thanks.

I'm writing this on my phone, so I hope it works, but you really just need to use a JOIN.

$table_alpha = "alpha";
$table_beta  = "beta";

$sql = "
    SELECT id, title, catid, author
    FROM $table_alpha
    JOIN $table_beta USING(id) 
    WHERE catid = 105
";

The USING clause tells the query to treat id the thing to join on. That should make it safe to query for it by name without stating which id to retrieve (man I wish I could verify that, but no SQL on my phone :-p)

This should do the job:

SELECT a.id, b.author, a.title
FROM alpha AS a
INNER JOIN beta AS b
ON a.id = b.id
WHERE a.catid = 105;

Your query was quite close, you need to use a JOIN with a condition:

$table_alpha = "alpha";
$table_beta = "beta";

$sql = "
SELECT $table_alpha.id, title, author 
FROM $table_alpha
JOIN $table_beta 
ON $table_alpha.id=$table_beta.id
WHERE catid = 105
"