如何解决如何限制/偏移量查询，每个唯一ID返回几行？
| 我的问题是我需要从以下查询中分页数据：function search($search_term,$limit,$offset)
{
$id = $this->auth->get_user_id();
$query = $this->db->query(\"
SELECT user_id,first_name,cars_name,cars_id
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
WHERE user_id NOT LIKE \'$id\'
AND activated = 1
AND banned = 0
AND first_name LIKE \'%$search_term%\'
ORDER BY first_name ASC
\");
$search_data = array();
foreach ($query->result() as $row) {
$search_data[$row->user_id][\'name\'] = $row->first_name;
$search_data[$row->user_id][\'cars\'][$row->cars_id] = array(
\'cars_name\' => $row->cars_name);
}
return $search_data;
}
1 JOE HONDA 123
1 JOE TOYOTA 124
2 MAC VW 125
2 MAC HONDA 126
2 MAC TESLA 127
3 STU SUBARU 128
3 STU KIA 129
-----------
Page 1
-----------
1 JOE HONDA 123
TOYOTA 124
2 MAC VW 125
HONDA 126
------------
Page 2
------------
3 STU SUBARU 128
KIA 129
...
LIMIT $limit
OFFSET $offset;
\");
GROUP BY
解决方法
我看不到在一个查询中执行此操作的方法。我的解决方案是使用具有相同参数的查询通过分组获取唯一ID的计数：
SELECT COUNT(1) AS uid_count
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
GROUP BY user_profiles.user_id
WHERE user_id NOT LIKE \'$id\'
AND activated = 1
AND banned = 0
AND first_name LIKE \'%$search_term%\'
mysql_num_rows
GROUP BY
SELECT SQL_CALC_FOUND_ROWS
user_id,first_name,cars_name,cars_id
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
WHERE user_id NOT LIKE \'$id\'
AND activated = 1
AND banned = 0
AND first_name LIKE \'%$search_term%\'
GROUP BY user_id
ORDER BY first_name ASC
LIMIT 100
GROUP BY
ORDER BY
OFFSET
LIMIT
SQL_CALC_FOUND_ROWS
LIMIT
SELECT FOUND_ROWS() AS `count`
count
cars_name
cars_id
SELECT
user_id,GROUP_CONCAT(cars_name SEPARATOR \',\'),GROUP_CONCAT(cars_id SEPARATOR \',FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
WHERE user_id NOT LIKE \'$id\'
AND activated = 1
AND banned = 0
AND first_name LIKE \'%$search_term%\'
ORDER BY first_name ASC
LIMIT 100
1 JOE HONDA,TOYOTA 123,124
2 MAC VW,HONDA,TESLA 125,126,127
3 STU SUBARU,KIA 128,129
Page 1
----------------------
1 JOE HONDA 123
1 JOE TOYOTA 124
Page 2
----------------------
2 MAC VW 125
2 MAC HONDA 126
2 MAC TESLA 127
Page 3
----------------------
3 STU SUBARU 128
3 STU KIA 129
CREATE TEMPORARY TABLE `test`.`temp_user_ids` (
`id` INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,`user_id` INTEGER UNSIGNED NOT NULL,PRIMARY KEY (`id`)
)
ENGINE = MEMORY
INSERT INTO temp_user_ids
SELECT null,user_id
FROM user_profiles
LEFT JOIN cars
ON cars.id_fk = user_id
WHERE user_id NOT LIKE \'$id\'
AND activated = 1
AND banned = 0
AND first_name LIKE \'%$search_term%\'
ORDER BY user_id DESC /*insert in reverse order !*/
SELECT @current_id:= LAST_INSERT_ID()
SELECT count(*) as row_count,up.user_id,group_concat(cars_name) as car_names,group_concat(cars_id) as car_ids,FROM user_profiles up
LEFT JOIN cars
ON cars.id_fk = up.user_id
INNER JOIN temp_user_ids t
ON (t.user_id = up.user_id)
WHERE t.id = @current_id
GROUP BY up.user_id
ORDER BY cars.id
SELECT @current_id:= @current_id - 1;
car_names
car_ids
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