CODEWITHSUNDEEP
phpmysql
bhavdeep singh
bhavdeep singh

Reputation: 13

How can i insert data into a column of a table (out of 2 tables) such that user id matches in both of them?

How can I insert data into a column of a table (out of 2 tables) such that user id matches in both of them? table 1 is users and table 2 is comments

Here is the query I am using:

$query='INSERT INTO comments VALUES('','','$comment','','') WHERE users.id=comments.id';

but it says an error:

Parse error: syntax error, unexpected '','' (T_CONSTANT_ENCAPSED_STRING) in F:\xampp\htdocs\my\lecture1.php on line 263

where line 263 is the query

Upvotes: 1

Views: 43

Answers (1)

Havenard
Havenard

Reputation: 27874

INSERT can only include new records. To modify the value of a field in an existing record, use UPDATE.

For instance:

UPDATE comments SET comment = 'Blah, blah blah.' WHERE id = 1;

You can cross tables while using UPDATE, however I don't see any reason to do that in this case.

You can also use INCLUDE with ON DUPLICATE KEY trigger to create the record if it doesn't exist or update an existing one with the same query. The ON DUPLICATE KEY trigger is triggered when the insertion of the new record is impossible because the UNIQUE or PRIMARY KEY specified is already present in the table. Example:

INSERT INTO comments (id, comment) VALUES (1, 'Comment') ON DUPLICATE KEY UPDATE comment = 'Comment';

Upvotes: 1

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