如何查询构建的字符串选择

Question

我想做点什么

SELECT * FROM (
    SELECT ('reword#' || reword) || reword_faq as reword FROM me_review_entries re
) as re
WHERE re.reword = 'reword#2#SOME_FAQ'

我试着做

SELECT ('reword#' || reword) || reword_faq as foo FROM me_review_entries re
WHERE foo = 'reword#2#SOME_FAQ'

但我明白了：

ERROR:  column "foo" does not exist
LINE 2: WHERE foo = 'reword#2#SOME_FAQ'

这是唯一的做法吗？或者我可以改进吗？

Answer 1

我认为这取决于你的数据库，但foo列除了在查询中之外不存在，所以你可能需要这样做：

SELECT ('reword#' || reword) || reword_faq as foo FROM me_review_entries re
WHERE ('reword#' || reword) || reword_faq = 'reword#2#SOME_FAQ'