Question

我有一个使用多个MAX语句的查询，这些语句在使用单个MAX语句时有效。我被卡住了。以下作品：

SELECT 
MAX(CASE WHEN meta_key = '_pronamic_google_maps_latitude' THEN meta_value END)lat,
FROM wp_postmeta WHERE post_id IN (SELECT id from wp_posts where post_name = 'Idaho')

但这不是：

SELECT 
MAX(CASE WHEN meta_key = '_pronamic_google_maps_latitude' THEN meta_value END)lat,
MAX(CASE WHEN meta_key = '_pronamic_google_maps_longitude' THEN meta_value END)long
FROM wp_postmeta WHERE post_id IN (SELECT id from wp_posts where post_name = 'Idaho')

怎么了？

Answer 1

由于语法高亮显示long为reserved word，因此您必须将其转义为将其用作别名。 Example

SELECT 
  MAX(CASE WHEN meta_key = '_pronamic_google_maps_latitude' THEN meta_value END) AS lat,
  MAX(CASE WHEN meta_key = '_pronamic_google_maps_longitude' THEN meta_value END) AS `long`
FROM wp_postmeta WHERE post_id IN (SELECT id from wp_posts where post_name = 'Idaho')

MySQL多个MAX语句导致语法错误？

1 个答案: