Perl 脚本：带 IF 的 SQL 命令显示为语法错误

Question

在 MySQL DB 中工作的带有 IF 的 SQL 命令显示为语法错误。

if (exists(
    SELECT * FROM tanss.leistungen
    where
    firmenid = Tanss
    and date(FROM_UNIXTIME(datum)) >= DATE_ADD(DATE_ADD(MAKEDATE(YEAR(CURRENT_DATE), 1), INTERVAL MONTH(CURRENT_DATE)-6 MONTH), INTERVAL -0 DAY)
    and date(FROM_UNIXTIME(datum)) < DATE_ADD(DATE_ADD(MAKEDATE(YEAR(CURRENT_DATE), 1), INTERVAL MONTH(CURRENT_DATE) MONTH), INTERVAL -0 DAY)
) =0 ,"ohne","vorhanden") as Leistung

或更简单，例如

if(niederlassung.name is null,"Niederlassung Warendorf",niederlassung.name) as Niederlassung

cmd 的错误 output 是：

Bareword在 C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl 第 123 行，靠近 ") =0,"ohne" （可能是从第 115 行开始的失控的多行 "" 字符串）（ohne之前缺少运算符？ ) String found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 123, near "ohne","" Bareword found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 123, near "", “vorhanden”（在 vorhanden之前缺少运算符？）字符串在 C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl 第 123 行，靠近“left join tanss.anfahrtpauschale_preise as anfahrtfirma on anfahrtfirma.linkid.zoneIDtrag.id 和= "" （上一行缺少分号？ ）

或者

Bareword在 C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl 第 115 行，靠近“if（ niederlassung.name is null”“Niederlassung”（可能是一个失控的多行“ Doline”）附近的第 115 行找到操作员预期的位置你需要预先声明 if 吗？ ）

我正在使用 DBD::ODBC

有没有什么方法可以让 Perl 接受这种扩展的 SQL 命令，而无需我在脚本中编辑它，就像我目前正在做的那样？

更新：

• SQL 是一个字符串，完整的语句有引号
• SQL 语句 100% 工作

代码的主要部分（但仍然不是完整的代码）：

    sub getLeadingMethode{
    $SQL = "
    SELECT
        vertrag.ID as VertragsDBid,
        vertrag.name as Vertragsart,
        vertrag.datumvon as von,
        vertrag.datumbis as bis,
        firmen.displayID as Tanss,
        firmen.name as Kundenname,
    if (exists(
            SELECT * FROM tanss.leistungen
            where
            firmenid = Tanss
            and date(FROM_UNIXTIME(datum)) >= DATE_ADD(DATE_ADD(MAKEDATE(YEAR(CURRENT_DATE), 1), INTERVAL MONTH(CURRENT_DATE)-6 MONTH), INTERVAL -0 DAY)
            and date(FROM_UNIXTIME(datum)) < DATE_ADD(DATE_ADD(MAKEDATE(YEAR(CURRENT_DATE), 1), INTERVAL MONTH(CURRENT_DATE) MONTH), INTERVAL -0 DAY)
        ) =0 ,"$4","$5") as Leistung

    FROM tanss.vertrag
        left join tanss.firmen on tanss.firmen.ID = vertrag.firmenID
        left join tanss.anfahrtpauschale_preise as anfahrtfirma on anfahrtfirma.linkID = vertrag.id and anfahrtfirma.zoneID = "$6" and anfahrtfirma.linktypid = "$7"
        left join (select * from tanss.firmen_fahrt as fahrt_1 where km_einfach =(select min(km_einfach) from tanss.firmen_fahrt where firmenID = fahrt_1.firmenid) ) as anfahrt on anfahrt.firmenID = firmen.id
        left join tanss.firmen as niederlassung on niederlassung.id = anfahrt.mandantID
        left join tanss.f_info_werte as vb on vb.firmenid = firmen.id and defID = "$8";";

完整的错误信息：

C:\Entwicklung\LWEI_SampleCodes>sampleCode20.pl
Scalar found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 115, near ") =0 ,"$4"
  (Might be a runaway multi-line "" string starting on line 100)
        (Missing operator before $4?)
String found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 115, near "$4",""
        (Missing operator before ","?)
Scalar found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 115, near "","$5"
        (Missing operator before $5?)
String found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 115, near "left join tanss.anfahrtpauschale_preise as anfahrtfirma on anfahrtfirma.linkID = vertrag.id and anfahrtfirma.zoneID = ""
        (Missing semicolon on previous line?)
Scalar found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 119, near "left join tanss.anfahrtpauschale_preise as anfahrtfirma on anfahrtfirma.linkID = vertrag.id and anfahrtfirma.zoneID = "$6"
  (Might be a runaway multi-line "" string starting on line 115)
        (Do you need to predeclare left?)
String found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 119, near "$6" and anfahrtfirma.linktypid = ""
        (Missing operator before " and anfahrtfirma.linktypid = "?)
Scalar found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 119, near "" and anfahrtfirma.linktypid = "$7"
        (Missing operator before $7?)
String found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 119, near "left join tanss.f_info_werte as vb on vb.firmenid = firmen.id and defID = ""
        (Missing semicolon on previous line?)
Scalar found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 122, near "left join tanss.f_info_werte as vb on vb.firmenid = firmen.id and defID = "$8"
  (Might be a runaway multi-line "" string starting on line 119)
        (Do you need to predeclare left?)
String found where operator expected at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 122, near """
        (Missing semicolon on previous line?)
syntax error at C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl line 115, near ") =0 ,"$4"
Execution of C:\Entwicklung\LWEI_SampleCodes\sampleCode20.pl aborted due to compilation errors.

Answer 1

    $SQL = "
    .......
        ) =0 ,"$4","$5") as Leistung

双引号字符串中有未转义的双引号。 这会破坏你的报价。 您需要转义引号，例如：

    $SQL = "
    .......
        ) =0 ,\"$4\",\"$5\") as Leistung

或者使用qq / q ...

    $SQL = qq#
    .......
        ) =0 ,"$4","$5") as Leistung
    #

或使用heredoc ....

    $SQL = <<"END_SQL"
    .......
        ) =0 ,"$4","$5") as Leistung
END_SQL

或者，如果您使用的是DBI ，而不是在字符串中插入变量，您应该使用占位符

    $SQL = "
    .......
        ) =0 , ? , ?) as Leistung

稍后在您的执行语句中提供变量。

$dbi->prepare($SQL);        # sample code, not for use
$dbi->execute($4, $5);

此外，变量$4 、 $5等是正则表达式匹配捕获的内置变量。 使用它们与正则表达式捕获分离可能很危险。 我假设你正在做类似的事情。

if ($foo =~ /(...)(...)..../) {   # capturing $1 .... $7 etc
    getLeadingMethode();          # relying on global scope variables

但最好将值与子调用一起传递，如下所示：

if ($foo =~ /(...)(...)..../) {     # capturing $1 .... $7 etc
    getLeadingMethode($4, $5, $7);  # passing values directly, encapsulated approach

就像我上面所说的，对于 DBI，您希望使用占位符并让模块处理引用。