为啥查询不返回值？
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【中文标题】为啥查询不返回值？【英文标题】：Why is the query not returning values?为什么查询不返回值？ 【发布时间】：2021-10-26 14:18:38 【问题描述】：我正在将我的 perl 脚本从旧版本迁移到从 v5.8.4 到 Perl 版本 (v5.16.3) 的过程中，遇到了查询未获取结果的问题。
在查询返回时测试了以下场景
多行单列 -> 工作正常 单行单列 -> 工作正常 多行多列 -> 不工作 单行多列 -> 不工作不确定发生了什么。它不是抛出错误，而是返回 0 条记录
my $sth;
my $prepareCapture = capture_merged
$sth = $dbh->prepare($self->_generatedSQL);
;
$self->addProcessLogMessage($prepareCapture) if defined $prepareCapture;
if (!defined $sth)
$self->addProcessLogMessage('[PWX.extractPWXFile]: DBI::errstr = ' . $DBI::errstr);
$self->addErrorMessage('PWX.extractPWXFile', 'Prepare of generated SQL against the PWX database failed');
return -1;
# Execute generated SQL against the PWX database
$self->addProcessLogMessage('[PWX.extractPWXFile]: Executing generated SQL against PWX database');
my $executeRC;
my $executeCapture = capture_merged
$executeRC = $sth->execute();
;
$self->addProcessLogMessage(sprintf('[PWX.Debugging sth Value-->%s',$sth));
$self->addProcessLogMessage(sprintf('[PWX.Debugging executeCapture -->%s',$executeCapture));
$self->addProcessLogMessage(sprintf('[PWX.Debugging executeRC Val -->%s',$executeRC));
$self->addProcessLogMessage($executeCapture) if defined $executeCapture;
if (!defined $executeRC)
$self->addProcessLogMessage('[PWX.extractPWXFile]: DBI::errstr = ' . $DBI::errstr);
$self->addErrorMessage('PWX.extractPWXFile', 'Execution of generated SQL against the PWX database failed');
return -1;
# Store details in local variables
my $exportFileNm = PCF::Helpers::PathHelper->resolveExportFile($self->_srcSysCd,$self->_fileNm);
my $fileDelimiter = $self->_fileDelimiter;
my $fileDetailType = $self->_fileDetailType;
my $recordCount = 0;
# Open the export file, ready for writing to
$self->addProcessLogMessage('[PWX.extractPWXFile]: Opening target object file');
$self->addProcessLogMessage(sprintf('[PWX.extractPWXFile]: Export File = %s', $exportFileNm));
if (open(EXPORT_HANDLE, sprintf('> %s', $exportFileNm)))
# Output Header Record
$self->addProcessLogMessage('[PWX.extractPWXFile]: Outputting Header Record to target object file');
print EXPORT_HANDLE $self->_fileHeaderType
, $fileDelimiter
, $self->_fileRunNbr
, $fileDelimiter
, $self->_fileRunDt
, $fileDelimiter
, $self->_fileDescription
, $fileDelimiter
, $self->_runtimeParameters->'ProcInstId'
, "\n";
# Fetch the resultset and output a Detail Record
my $refRowArray;
my $colIndex;
my $colData;
my $colOutput;
my $colOutput1;
my $colOutput2;
my $colOutput3;
$self->addProcessLogMessage('[PWX.extractPWXFile]: Outputting Detail Record(s) to target object file');
while (1)
$refRowArray = $sth->fetchrow_arrayref();
last if !defined $refRowArray;
# Iterate through the columns and build a hash for output
print EXPORT_HANDLE $fileDetailType;
$colIndex = 0;
$colOutput1 = '';
$colOutput2 = '';
$colOutput3 = '';
foreach $colData (@$refRowArray)
# Perform left and right TRIM inline
$colOutput = $colData;
$colOutput =~ s/^\s+//;
$colOutput =~ s/\s+$//;
# Replace CRLF, CR, LF and Pipes with a space
$colOutput =~ s/(\r\n|\r|\n|\|)/ /g;
# If the column data has not returned a NULL value
# but rather contains all blanks then output a single blank
if ((defined $colData)
&& (length($colOutput) == 0))
$colOutput = ' ';
# If the first column, which is DTL__CAPXTIMESTAMP, format into ANSI standard
# Does not apply to sources that have EffStrtTs, RecTpCd as first 2 columns.
if ($colIndex == 0 && $self->_srcHasProcCols eq 'N')
$colOutput = substr($colOutput, 0, 4)
. '-'
. substr($colOutput, 4, 2)
. '-'
. substr($colOutput, 6, 2)
. ' '
. substr($colOutput, 8, 2)
. ':'
. substr($colOutput, 10, 2)
. ':'
. substr($colOutput, 12, 2)
. '.'
. substr($colOutput, 14, 6);
# If the extract is incremental, substitute capx_action values of "I" and "U" for "M"
elsif (($incrementalLoad == 1) && ($colIndex == 1))
if ($colOutput eq 'I' || $colOutput eq 'U')
$colOutput = 'M';
# If the extract is bulk VSAM DFSORT, substitute RecTpCd value 'F' with the derived value from REC_TYP_CDE column.
# REC_TYP_CDE column is at the end of the record, so do not write to file until end of record is reached.
if ($attrDfSortFlag eq 'Y')
#keep the column values in two strings
if ($colIndex > 1)
$colOutput3 .= $fileDelimiter . $colOutput;
elsif ($colIndex == 0)
$colOutput1 = $colOutput;
if ($colIndex == $#$refRowArray)
#derive RecTpCd value: 1 insert, 2 update, 3 delete
if (($colOutput == 1) || ($colOutput == 2))
$colOutput2 = 'M';
elsif ($colOutput == 3)
$colOutput2 = 'D';
else
if (!defined $colOutput)
$colOutput2 = 'Null';
else
$colOutput2 = $colOutput;
$self->addErrorMessage('PWX.extractPWXFile', "VSAM DFSORT File: Invalid REC_TYP_CDE value from source. expecting 1,2 or 3 but received $colOutput2");
return -1;
#append the strings to make the record
print EXPORT_HANDLE $fileDelimiter, $colOutput1, $fileDelimiter, $colOutput2, $colOutput3;
else
print EXPORT_HANDLE $fileDelimiter, $colOutput;
# Increment the column counter
$colIndex++;
print EXPORT_HANDLE "\n";
# Increment the record counter
$recordCount++;
# Check if there is any error while fetching. fail if there is.
if ($DBI::err)
$self->addErrorMessage('PWX.extractPWXFile', "Connection to database lost due to following error: $DBI::errstr");
$self->addErrorMessage('PWX.extractPWXFile', "The following number of records were extracted before exiting : $recordCount ");
return -1;
查询：
SELECT col1, col2, col3, col4, col5, col6, col7, col8, col9, col10, col11, col12,
col13, col14, col15, col16, col17, col18, col19, col20, col21, col22
FROM mmm.cont
WHERE datets >= DATEADD(HOUR,-2,'2021-06-17 14:30:40.110000')
AND datets < '2021-07-22 20:05:32.620000'
AT ISOLATION READ COMMITTED
【问题讨论】：
请显示所有 Perl 代码，而不仅仅是循环。显示调用查询以设置$sth 的代码。你在做什么错误检查？
更新到 8 年前的 Perl 版本似乎有点奇怪。为什么不升级到更新的版本？
添加完整代码
【参考方案1】：
返回 0 条记录
你怎么知道的？如果返回一些行或不返回行，您向我们展示的代码没有什么不同。我怀疑您为了与我们共享代码而过度简化了代码，并在此过程中删除了导致您的问题的部分。
我认为这不会导致您的问题，但我只是指出您当前的代码可以简化为：
while ($refRowArray = $sth->fetchrow_arrayref())
# do nothing
【讨论】：
嗨，戴夫，我放了一些日志，打印返回的记录数。在这种情况下，它不返回任何记录。但是，如果我用简单的查询替换它，说我知道将返回 1 条记录，那么日志记录还指示它的重新调整记录，并且在 while 循环内我正在写入文件，因此它也在写入文件。 即使我用简单查询替换选择查询中的 2 列而不是 1 列，即使它失败了。如果 Select 查询有超过 1 列，则它不会从 db 返回任何内容。 您好，非常感谢您对此的任何帮助。我是 perl 脚本的新手，无法继续。请帮忙！！！以上是关于为啥查询不返回值？的主要内容，如果未能解决你的问题，请参考以下文章
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