用于匹配某些 Table 的复杂 Where 子句的正则表达式

Question

我有一个程序采用受限制的 SQL 服务器 WHERE 子句并删除针对特定 table 的部分。这种 where 子句的一个例子是

AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null) AND ([Episode].[YN] = 'Y')

我需要删除查询中使用 table Episode 的所有部分，并考虑 (、) 来括起语句和方括号用于字段名称等。为此，我有

private string BuildResourceWhereClauses(string whereClauses, string episodeTable)
{
    Regex r = new Regex(
        $"AND\s+\(*\[*{episodeTable}\]*\.\[*\w+\]*\s*(=|<>|<=|>=)(\s*\'*(NULL|\S+|\((.*?)\)+)\'*\s*\)*){{1}}",
        RegexOptions.IgnoreCase);

    string tmp = r.Replace(whereClauses, String.Empty).Trim();
    return $" {tmp}";
}

这很有效，returning

AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null)

但是现在，有人要求我扩展它，以便我们允许所有 SQL WHERE 子句语法。所以我们现在可以有一个像

这样的 where 子句

AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null) AND ([Episode].[YN] = 'Y') AND (Episode.Paste = 'Y') AND [Episode].[Source] = '%6' AND [Episode].[TFC] NOT IN ('LWC', 'POD')

那我们要"parse"，所以我把上面的方法修改为

private string BuildResourceWhereClauses(string whereClauses, string episodeTable)
{
    Regex r = new Regex(
        $"AND\s+\(*\[*{episodeTable}\]*\.\[*\w+\]*\s*(=|<>|<=|>=|LIKE|IN|NOT IN|IS|BETWEEN\s+\w+\s+AND)(\s*\'*(NULL|\S+|\((.*?)\)+)\'*\s*\)*){{1}}",
        RegexOptions.IgnoreCase);

    string tmp = r.Replace(whereClauses, String.Empty).Trim();
    return $" {tmp}";
}

使用 episodeTable = "Episode" 我得到 returned

AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null) 'POD')

此缺失匹配 AND (Episode.Paste = 'Y')、AND [Episode].[Source] = '%6' 和 AND [Episode].[TFC] NOT IN ('LWC', 'POD')。

正则表达式有什么问题我如何将其修改为我想要的return？
与其让这个正则表达式变得更复杂，不如简化一下？

感谢您的宝贵时间。

下面的答案删除了我以前的一些功能（我的错是没有规定我需要保留它！还有什么让它如此困难 - 捕获所有情况”）。所以我需要匹配这个字符串

AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null) AND ([Episode].[YN] = 'Y') AND Episode.FRC BETWEEN 10 AND 20 AND Episode.Dt between '2011/02/25' and '2011/02/27' AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null) AND ([Episode].[YN] = 'Y' AND Episode.TFC IS NOT LIKE '655r%') AND (Episode.Paste = 'Y') AND [Episode].[Source] IS NOT LIKE '%6' AND [Episode].[TFC] NOT IN ('LWC', 'POD') AND [Episode].[TFC] IS NULL

所以在 C# 中，我需要以下代码

string whereClaues = 
    "AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null) " + 
    "AND ([Episode].[YN] = 'Y') AND Episode.FRC BETWEEN 10 AND 20 AND Episode.Dt between '2011/02/25' and '2011/02/27' " +
    "AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null) AND ([Episode].[YN] = 'Y' AND Episode.TFC IS NOT LIKE '655r%') " +
    "AND (Episode.Paste = 'Y') AND [Episode].[Source] IS NOT LIKE '%6' AND [Episode].[TFC] NOT IN ('LWC', 'POD') AND [Episode].[TFC] IS NULL";
string tmp = r.Replace(whereClauses, String.Empty).Trim();

将 tmp 设为

AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null) AND (Util.Source='IP%' AND Util.ReqType = 'IP') AND (Util.Epinum is null)

删除所有 Episode 子句，包括 BETWEEN 语句以及 IS NOT NULL 和 IS NULL 语句。

有

AND\s+\(*\[*Episode\]*\.\[*\w+\]*\s*(<>|[><]?=|(?:NOT\s+)?IN|(?:IS\s+)?LIKE|(?:IS\s+NOT\s+)?LIKE|BETWEEN(\s*\'*(\((.*?)\)+|NULL|\S+)\'*\s*\)*)AND)(\s*\'*(\((.*?)\)+|NULL|\S+)\'*\s*\)*)

但这不匹配

Episode.TFC IS NULL

Answer 1

看来您可以通过以下方式扩展您的模式：

$@"AND\s+\(*\[*{episodeTable}\]*\.\[*\w+\]*\s*(<>|[><]?=|(?:NOT\s+)?IN)(\s*\'*(\((.*?)\)+|NULL|\S+)\'*\s*\)*)"

参见regex demo here。

详情

AND - 一个子串
\s+ - 1+ 个空格
\(* - 0+ ( 个字符
\[* - 0+ [ 个字符
Episode - table
\]* - 0+ ] 个字符
\. - 一个 . 字符
\[* - 0+ [ 个字符
\w+ - 1+ 个单词字符
\]* - 0+ ] 个字符
\s* - 0+ 个空格
(<>|[><]?=|(?:NOT\s+)?IN) - 第 1 组：<>、<=、>=、=、NOT IN 或 IN
(\s*\'*(\((.*?)\)+|NULL|\S+)\'*\s*\)*) - 第 2 组：
- \s* - 0+ 个空白字符
- \'* - 0+ ' 个字符
- (\((.*?)\)+|NULL|\S+) - 第 3 组：
  - \( - 一个(
  - (.*?) - 第 4 组：除换行符外的任何 0+ 个字符尽可能少
  - \)+ - 1+ ) 个字符
  - | - 或
  - NULL - NULL 子串
  - | - 或
  - \S+ - 1+ 个非空白字符
- \'* - 0+ ' 个字符
- \s* - 0+ 个空格
- \)* - 0+ ) 个字符。

用于匹配某些 Table 的复杂 Where 子句的正则表达式

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