问题
I'm getting an error Query failed: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '5,7,6,9,13 ORDER BY n.date DESC' at line 5. Can anyone point out what's wrong? Thanks
$news_query = 'SELECT u.id as userId, u.username, n.id as newsId, n.action, n.date
FROM newsfeed as n
JOIN users as u on n.userId = u.id
WHERE
userId in '.implode(',', array_map('intval', $myfriends)).' &&
userId == :myId // posts by me
ORDER BY n.date DESC
';
回答1:
The comparison operator:
userId == :myId
In SQL the equality operator is =, not ==.
From the error message it appears that the above snippet, when the value is inserted into the query, looks like this:
userId == 5,7,6,9,13
That is not a valid comparison, even if you used the right operator. If you want to compare userId against a list of values then you should use the IN operator and a tuple (a set of values):
userId IN (5,7,6,9,13)
Response to comment
You could change your code to:
$tuple = implode(',', array_map('intval', $myfriends));
$news_query = <<< SQL
SELECT
u.id AS userId,
u.username,
n.id AS newsId,
n.action,
n.date
FROM
newsfeed AS n
JOIN
users AS u ON n.userId = u.id
WHERE
userId IN ($tuple) AND
userId = :myId
ORDER BY
n.date DESC
SQL;
You should also qualify the userId field in the WHERE clause; i.e. put u. or n. in-front of it, so that there is no ambiguity.
回答2:
Wrap your list in parentheses here:
WHERE userId in ('.implode(',', array_map('intval', $myfriends)).') &&
^ here ^ and here
and on the next line replace == with = (thanks to jeroen for picking this up)
userId = :myId
^ here
来源：https://stackoverflow.com/questions/24275793/mysql-syntax-error-in-query