mysql - 如何使用 INSERT INTO 多次选择插入？

Question

我正在尝试为表中的每个字段分别插入两个数据，如下所示：

INSERT INTO `wp_postmeta` (post_id, meta_key, meta_value)
SELECT post_id, 'custom', custom
SELECT post_id, '_custom', 'field_514e91e73640d'
FROM `wp_temp`
WHERE custom IS NOT NULL

但是，这不起作用。无论如何在MySQL的一个查询中实现这一点？谢谢。

Answer 1

INSERT INTO `wp_postmeta` (post_id, meta_key, meta_value)
SELECT post_id, 'custom', custom FROM `wp_temp` WHERE custom IS NOT NULL
UNION ALL
SELECT post_id, '_custom', 'field_514e91e73640d' FROM `wp_temp` WHERE custom IS NOT NULL

Answer 2

您将需要一个单独的FROMandWHERE子句SELECT，但可以使用 UNION 或 UNION ALL。

INSERT INTO `wp_postmeta` (post_id, meta_key, meta_value)
SELECT post_id, 'custom', custom
FROM `wp_temp`
WHERE custom IS NOT NULL
UNION 
SELECT post_id, '_custom', 'field_514e91e73640d'
FROM `wp_temp`
WHERE custom IS NOT NULL

Answer 3

是的UNION ALL

INSERT INTO `wp_postmeta` (post_id, meta_key, meta_value)
SELECT post_id, '_custom', 'field_514e91e73640d'
FROM `wp_temp`
WHERE custom IS NOT NULL

UNION ALL

SELECT post_id, 'custom', custom
FROM `wp_temp`
WHERE custom IS NOT NULL