我有像这样的表格:
Table1 Table2
name1 | link_id name2 | link_id
text 1 text 2
text 2 text 4
And I wanna have result:
name1 name2 link_id
text text 1
text text 2
text text 4
我该怎么做?
添加: 对不起,我的英语不好。我有一个设备、设备模型和设备类型表,其中包含重复的字段counter_set_id。我想从counter_set选择字段,包括所有的counter_set_id值。我只需要从counter_set_id字段中获取值。
现在我有这个查询:
SELECT `dev`.`counter_set_id`, `mod`.`counter_set_id`, `type`.`counter_set_id`
FROM `device` AS `dev`
LEFT JOIN `device_model` AS `mod` ON `dev`.`device_model_id` = `mod`.`id`
LEFT JOIN `device_type` AS `type` ON `mod`.`device_type_id` = `type`.`id`
WHERE `dev`.`id` = 4;
这个返回了3列,但我需要所有的值在一列中。
我认为这是最终版本:
SELECT `dev`.`counter_set_id`
FROM `device` AS `dev` LEFT OUTER JOIN
`device_model` AS `mod` ON `dev`.`device_model_id` = `mod`.`id`
WHERE `dev`.`id` = 4 AND
`dev`.`counter_set_id` IS NOT NULL
UNION
SELECT `mod`.`counter_set_id`
FROM `device_model` AS `mod` LEFT OUTER JOIN
`device` AS `dev` ON `mod`.`id` = `dev`.`device_model_id`
WHERE `mod`.`counter_set_id` IS NOT NULL;