【问题标题】:What are the gotchas when converting a T-SQL statement into a JavaScript RegExp将 T-SQL 语句转换为 JavaScript RegExp 时有什么问题
【发布时间】:2023-03-04 08:59:02
【问题描述】:

我有大量从我管理的服务器记录的 T-SQL 语句。我正在尝试将它们归结为每个实例。

这是其中之一:

SELECT TBLLANGUAGE.NAME AS NAME1, TBLLANGUAGE_1.NAME AS NAME2, 
TBLLANGUAGELANGUAGE.LNGFKCHILD, TBLLANGUAGELANGUAGE.LNGFKPARENT, 
TBLLANGUAGELANGUAGE.STYLE, TBLLANGUAGELANGUAGE.EXTENT, 
TBLLANGUAGELANGUAGE.NATURE, TBLSOURCE.TXTTITLE, TBLSOURCE_1.TXTTITLE AS 
SURTITLE FROM ((((TBLLANGUAGE LEFT JOIN TBLLANGUAGELANGUAGE ON 
TBLLANGUAGE.ID = TBLLANGUAGELANGUAGE.LNGFKPARENT) LEFT JOIN TBLLANGUAGE 
AS TBLLANGUAGE_1 ON TBLLANGUAGELANGUAGE.LNGFKCHILD = TBLLANGUAGE_1.ID) 
LEFT JOIN TBLLANGLANGSOURCE ON TBLLANGUAGELANGUAGE.IDLANGLINK = 
TBLLANGLANGSOURCE.LNGFKLANGLINK) LEFT JOIN TBLSOURCE ON 
TBLLANGLANGSOURCE.LNGFKSOURCE = TBLSOURCE.IDSOURCE) LEFT JOIN TBLSOURCE 
AS TBLSOURCE_1 ON TBLSOURCE.LNGPARTOF = TBLSOURCE_1.IDSOURCE WHERE 
(((TBLLANGUAGELANGUAGE.LNGFKPARENT) = 8687)) OR 
(((TBLLANGUAGELANGUAGE.LNGFKCHILD) = 8687)) ORDER BY 
IIF(TBLLANGUAGELANGUAGE.LNGFKPARENT = 8687,'B','A'), TBLLANGUAGE.NAME, 
TBLLANGUAGE_1.NAME;

我想将其转换为 JavaScript 正则表达式,将\d 的数字替换为'.*',将撇号之间的内容替换为'.*'

到目前为止,我在 Deno 方面已经做到了这一点:

function getPattern(text: string): string {
  text = text.replace(/\(/g, "\\x28")
    .replace(/\)/g, "\\x29")
    .replace(/\$/g, "\\x24")
    .replace(/\^/g, "\\x5e")
    .replace(/\./g, "\\x2e")
    .replace(/\*/g, "\\x2a")
    .replace(/\[/g, "\\x5b")
    .replace(/\]/g, "\\x5d")
    .replace(/\?/g, "\\x3f");

  [ "\\<\s\\>", "\\<", "\\<=", "=", "\\>=", "\\>"].forEach((op) => {
    const numberPattern = new RegExp(`\\s${op}\\s(\\d+)`, "g");
    text.match(numberPattern)?.forEach((e) => {
      text = text.replace(e, ` ${op} \\d+`);
    });
  });

  //const textPattern = /'[^']*'\s/g;
  const textPattern = /\s*'.*'\s*/g;
  text.match(textPattern)?.forEach((e) => {
    //const eLength = e.length;
    text = text.replace(e, "\\s*'.*'\\s*");
  });

  return text; //.replace(/\</g, "\\x3c")
    //.replace(/\>/g, "\\x3e");
}

这会将上述语句呈现为

SELECT TBLLANGUAGE\x2eNAME AS NAME1, TBLLANGUAGE_1\x2eNAME AS NAME2, 
TBLLANGUAGELANGUAGE\x2eLNGFKCHILD, TBLLANGUAGELANGUAGE\x2eLNGFKPARENT, 
TBLLANGUAGELANGUAGE\x2eSTYLE, TBLLANGUAGELANGUAGE\x2eEXTENT, 
TBLLANGUAGELANGUAGE\x2eNATURE, TBLSOURCE\x2eTXTTITLE, 
TBLSOURCE_1\x2eTXTTITLE AS SURTITLE FROM \x28\x28\x28\x28TBLLANGUAGE 
LEFT JOIN TBLLANGUAGELANGUAGE ON TBLLANGUAGE\x2eID = 
TBLLANGUAGELANGUAGE\x2eLNGFKPARENT\x29 LEFT JOIN TBLLANGUAGE AS 
TBLLANGUAGE_1 ON TBLLANGUAGELANGUAGE\x2eLNGFKCHILD = 
TBLLANGUAGE_1\x2eID\x29 LEFT JOIN TBLLANGLANGSOURCE ON 
TBLLANGUAGELANGUAGE\x2eIDLANGLINK = 
TBLLANGLANGSOURCE\x2eLNGFKLANGLINK\x29 LEFT JOIN TBLSOURCE ON 
TBLLANGLANGSOURCE\x2eLNGFKSOURCE = TBLSOURCE\x2eIDSOURCE\x29 LEFT JOIN 
TBLSOURCE AS TBLSOURCE_1 ON TBLSOURCE\x2eLNGPARTOF = 
TBLSOURCE_1\x2eIDSOURCE WHERE 
\x28\x28\x28TBLLANGUAGELANGUAGE\x2eLNGFKPARENT\x29 = \d+\x29\x29 OR 
\x28\x28\x28TBLLANGUAGELANGUAGE\x2eLNGFKCHILD\x29 = \d+\x29\x29 ORDER 
BY IIF\x28TBLLANGUAGELANGUAGE\x2eLNGFKPARENT = \d+,\s*'.*'\s*\x29, 
TBLLANGUAGE\x2eNAME, TBLLANGUAGE_1\x2eNAME;

我正在将各种组件转换为它们的 \xnn 表单,因为我阅读文档的方式显然 new RegExp() 不够聪明,无法看到嵌入的 ( 并且不认为我在定义一个组在正则表达式中。也就是说,光说似乎还不够

const pattern = new RegExp("SELECT TBLLANGUAGE.NAME (etcetera)","gi");

我是不是读错了文档,有没有更好的方法?不,我不想编写 T-SQL 解析器,除非有非常非常好的理由。

稍后

通过使用不同的模式匹配方法,我基本上解决了我的问题。请在DEV 上查看Extracting example SQL statements from a log

【问题讨论】:

  • 仅供参考,我强烈建议您养成在写作时使用换行符和空格的习惯。 900 多个字符长的单行代码是出了名的难以阅读。
  • 这不是 RegExp 构造函数的问题,而是发生了 两个 解析操作的事实:第一个,当字符串语法解释字符串(它不知道它是正则表达式),并且该语法 also 在该上下文中使用反斜杠作为转义序列。只有这样,解析后的字符串值才会传递给构造函数,构造函数将开始 second 解析。
  • 已采纳建议。帖子更新了。谢谢你,@Larnu
  • 我的回答好运吗?
  • @MonkeyZeus 它几乎可以工作。我正在创建两个版本的 Deno 脚本,一个使用您的技术,另一个使用更简单的标记化方法。我希望将两者都放在 dev.to 上。我可能会给你“打勾”,但实际上使用的是标记器方法。

标签: javascript sql-server regex tsql deno


【解决方案1】:

我不完全理解您想要实现的目标,但如果是:

将此 SQL 语句转换为可以找到其他类似 SQL 的有效正则表达式

那么这样就可以了:

var sql = `SELECT TBLLANGUAGE.NAME AS NAME1, TBLLANGUAGE_1.NAME AS NAME2, 
TBLLANGUAGELANGUAGE.LNGFKCHILD, TBLLANGUAGELANGUAGE.LNGFKPARENT, 
TBLLANGUAGELANGUAGE.STYLE, TBLLANGUAGELANGUAGE.EXTENT, 
TBLLANGUAGELANGUAGE.NATURE, TBLSOURCE.TXTTITLE, TBLSOURCE_1.TXTTITLE AS 
SURTITLE FROM ((((TBLLANGUAGE LEFT JOIN TBLLANGUAGELANGUAGE ON 
TBLLANGUAGE.ID = TBLLANGUAGELANGUAGE.LNGFKPARENT) LEFT JOIN TBLLANGUAGE 
AS TBLLANGUAGE_1 ON TBLLANGUAGELANGUAGE.LNGFKCHILD = TBLLANGUAGE_1.ID) 
LEFT JOIN TBLLANGLANGSOURCE ON TBLLANGUAGELANGUAGE.IDLANGLINK = 
TBLLANGLANGSOURCE.LNGFKLANGLINK) LEFT JOIN TBLSOURCE ON 
TBLLANGLANGSOURCE.LNGFKSOURCE = TBLSOURCE.IDSOURCE) LEFT JOIN TBLSOURCE 
AS TBLSOURCE_1 ON TBLSOURCE.LNGPARTOF = TBLSOURCE_1.IDSOURCE WHERE 
(((TBLLANGUAGELANGUAGE.LNGFKPARENT) = 8687)) OR 
(((TBLLANGUAGELANGUAGE.LNGFKCHILD) = 8687)) ORDER BY 
IIF(TBLLANGUAGELANGUAGE.LNGFKPARENT = 8687,'B','A'), TBLLANGUAGE.NAME, 
TBLLANGUAGE_1.NAME;`;

// First replace: account for JS regex special chars and escape with backslash to make them literal
// Second replace: get everything between single quotes and make it .+?
// Third replace: get all digit sequences and make them \d+
// Fourth replace: get all whitespace sequences and make them \s+
var sql_regex = sql.replace( /[.*+?^${}()|[\]\\]/g, '\\$&' )
                   .replace( /('.+?')/g, '\'.+?\'' )
                   .replace( /\d+/g, '\\d+' )
                   .replace( /\s+/g, '\\s+' );

console.log( sql_regex );

// Test if our regex matches the string it was built from
console.log( new RegExp( sql_regex, 'g' ).test( sql ) );

sql_regex 的值:

SELECT\s+TBLLANGUAGE\.NAME\s+AS\s+NAME\d+,\s+TBLLANGUAGE_\d+\.NAME
\s+AS\s+NAME\d+,\s+TBLLANGUAGELANGUAGE\.LNGFKCHILD,
\s+TBLLANGUAGELANGUAGE\.LNGFKPARENT,\s+TBLLANGUAGELANGUAGE\.STYLE,
\s+TBLLANGUAGELANGUAGE\.EXTENT,\s+TBLLANGUAGELANGUAGE\.NATURE,
\s+TBLSOURCE\.TXTTITLE,\s+TBLSOURCE_\d+\.TXTTITLE\s+AS\s+SURTITLE
\s+FROM\s+\(\(\(\(TBLLANGUAGE\s+LEFT\s+JOIN\s+TBLLANGUAGELANGUAGE\s+ON
\s+TBLLANGUAGE\.ID\s+=\s+TBLLANGUAGELANGUAGE\.LNGFKPARENT\)\s+LEFT
\s+JOIN\s+TBLLANGUAGE\s+AS\s+TBLLANGUAGE_\d+\s+ON
\s+TBLLANGUAGELANGUAGE\.LNGFKCHILD\s+=\s+TBLLANGUAGE_\d+\.ID\)\s+LEFT
\s+JOIN\s+TBLLANGLANGSOURCE\s+ON\s+TBLLANGUAGELANGUAGE\.IDLANGLINK\s+=
\s+TBLLANGLANGSOURCE\.LNGFKLANGLINK\)\s+LEFT\s+JOIN\s+TBLSOURCE\s+ON
\s+TBLLANGLANGSOURCE\.LNGFKSOURCE\s+=\s+TBLSOURCE\.IDSOURCE\)\s+LEFT
\s+JOIN\s+TBLSOURCE\s+AS\s+TBLSOURCE_\d+\s+ON\s+TBLSOURCE\.LNGPARTOF
\s+=\s+TBLSOURCE_\d+\.IDSOURCE\s+WHERE
\s+\(\(\(TBLLANGUAGELANGUAGE\.LNGFKPARENT\)\s+=\s+\d+\)\)\s+OR
\s+\(\(\(TBLLANGUAGELANGUAGE\.LNGFKCHILD\)\s+=\s+\d+\)\)\s+ORDER\s+BY
\s+IIF\(TBLLANGUAGELANGUAGE\.LNGFKPARENT\s+=\s+\d+,'.+?','.+?'\),
\s+TBLLANGUAGE\.NAME,\s+TBLLANGUAGE_\d+\.NAME;

注意:新行是肤浅的,只是为了便于阅读而添加

【讨论】:

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