How to use subqueries in MySQL - sql

Question

I have two tables.
Table user:
CREATE TABLE IF NOT EXISTS `user` (
`user_id` int(20) NOT NULL AUTO_INCREMENT,
`ud_id` varchar(50) NOT NULL,
`name` text NOT NULL,
`password` text NOT NULL,
`email` varchar(200) NOT NULL,
`image` varchar(150) NOT NULL,
PRIMARY KEY (`user_id`)
) ENGINE=InnoDB
and mycatch:
CREATE TABLE IF NOT EXISTS `mycatch` (
`catch_id` int(11) NOT NULL AUTO_INCREMENT,
`catch_name` text NOT NULL,
`catch_details` text NOT NULL,
`longitude` float(10,6) NOT NULL,
`latitude` float(10,6) NOT NULL,
`time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`image` varchar(150) NOT NULL,
`user_id` int(20) NOT NULL,
PRIMARY KEY (`catch_id`),
KEY `user_id` (`user_id`)
) ENGINE=InnoDB;
ALTER TABLE `mycatch`
ADD CONSTRAINT `mycatch_ibfk_1` FOREIGN KEY (`user_id`) REFERENCES `user` (`user_id`) ON DELETE CASCADE ON UPDATE CASCADE;
My goal is: I want to retrieve longitude and latitude from mycatch against given ud_id (from user) and catch_id (from mycatch) where ud_id = given ud_id and catch_id > given catch_id.
I used the query but fail to retrieve
SELECT ud_id=$ud_id FROM user
WHERE user_id =
(
SELECT user_id,longitude,latitude from mycatch
WHERE catch_id>'$catch_id'
)
The error is:
#1241 - Operand should contain 1 column(s)

Answer 1

First, try not to use subqueries at all, they're very slow in MySQL.
Second, a subquery wouldn't even help here. This is a regular join (no, Mr Singh, not an inner join):
SELECT ud_id FROM user, mycatch
WHERE catch_id>'$catch_id'
AND user.user_id = mycatch.user_id

Answer 2

Select m.longitude,m.latitude from user u left join mycatch m
on u.user_id =m.user_id
where u.ud_id=$ud_id and
m.catch_id >$catch_id