（Python /正则表达式）如何在两个给定单词之间选择文本？

Question

Langaue（Python3.X，Re 库）

我有一个字符串如下

import re
query_string = r'SELECT "a"."name", "a"."create_date", "a"."state", SUM("b"."cost") AS "amount", SUM("b"."cost") FILTER (WHERE "a"."state" = 'UNPAID') AS "paid", SUM("b"."cost") FILTER (WHERE "a"."state" = 'PAID') AS "unpaid" FROM "maintenance"'

我想选择“列名”，即"a"."name", "a"."create_date", "a"."state"。从上面的字符串。

介于"SELECT" and "SUM(.*)" 之间 任何帮助表示赞赏。

我试过下面的正则表达式模式

1. r'SELECT (.* ), [^(SUM(.* )]'

2. r'SELECT (.* ), SUM(.* )'

但两者都没有给出准确的结果

预期结果：

 "a"."name", "a"."create_date", "a"."state"(No comma at the endth)

Answer 1

你可以使用

(?:SELECT\s*)(.*?)(?:,\s*SUM.*)

创建单个捕获组。

两个(?:...) 组成非捕获组。
(.*?) 是一个非贪婪组，它将在第一个“SUM”之前停止，而不是最后一个。

Answer 2

用途：

(SELECT\s*)([^()]+)(,\s*SUM.*)

并将第二组与\2 一起使用。或者将\1 和\3 组替换为空。

测试here。

Answer 3

你可以使用：

sql = '''SELECT "a"."name", "a"."create_date", "a"."state", SUM("b"."cost") AS "amount", SUM("b"."cost") FILTER (WHERE "a"."state" = 'UNPAID') AS "paid", SUM("b"."cost") FILTER (WHERE "a"."state" = 'PAID') AS "unpaid" FROM "maintenance"'''

res = re.search(r'SELECT (.+?), SUM', sql)
print(res.group(1))

输出：

"a"."name", "a"."create_date", "a"."state"