sql - 如何查询构建的字符串选择

Question

我想做类似的事情

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

我尝试过

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

但我得到:

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

第一种方法是唯一的方法吗？或者我可以改进吗？

Answer 1

我认为这取决于您的数据库，但是 foo 列除了在查询中之外不存在，因此您可能必须这样做:

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