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.\" ========================================================================
.\"
.IX Title "DBIx::Class::ResultSetColumn 3pm"
.TH DBIx::Class::ResultSetColumn 3pm "2018-04-19" "perl v5.26.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
.Vb 2
\&  DBIx::Class::ResultSetColumn \- helpful methods for messing
\&  with a single column of the resultset
.Ve
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 3
\&  $rs = $schema\->resultset(\*(AqCD\*(Aq)\->search({ artist => \*(AqTool\*(Aq });
\&  $rs_column = $rs\->get_column(\*(Aqyear\*(Aq);
\&  $max_year = $rs_column\->max; #returns latest year
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
A convenience class used to perform operations on a specific column of
a resultset.
.SH "METHODS"
.IX Header "METHODS"
.SS "new"
.IX Subsection "new"
.Vb 1
\&  my $obj = DBIx::Class::ResultSetColumn\->new($rs, $column);
.Ve
.PP
Creates a new resultset column object from the resultset and column
passed as params. Used internally by \*(L"get_column\*(R" in DBIx::Class::ResultSet.
.SS "as_query"
.IX Subsection "as_query"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: \e[ $sql, @bind_values ]" 4
.el .IP "Return Value: \e[ \f(CW$sql\fR, \f(CW@bind_values\fR ]" 4
.IX Item "Return Value: [ $sql, @bind_values ]"
.PD
.PP
Returns the \s-1SQL\s0 query and bind vars associated with the invocant.
.PP
This is generally used as the \s-1RHS\s0 for a subquery.
.SS "next"
.IX Subsection "next"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $value" 4
.el .IP "Return Value: \f(CW$value\fR" 4
.IX Item "Return Value: $value"
.PD
.PP
Returns the next value of the column in the resultset (or \f(CW\*(C`undef\*(C'\fR if
there is none).
.PP
Much like \*(L"next\*(R" in DBIx::Class::ResultSet but just returning the
one value.
.SS "all"
.IX Subsection "all"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: @values" 4
.el .IP "Return Value: \f(CW@values\fR" 4
.IX Item "Return Value: @values"
.PD
.PP
Returns all values of the column in the resultset (or \f(CW\*(C`undef\*(C'\fR if
there are none).
.PP
Much like \*(L"all\*(R" in DBIx::Class::ResultSet but returns values rather
than result objects.
.SS "reset"
.IX Subsection "reset"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $self" 4
.el .IP "Return Value: \f(CW$self\fR" 4
.IX Item "Return Value: $self"
.PD
.PP
Resets the underlying resultset's cursor, so you can iterate through the
elements of the column again.
.PP
Much like \*(L"reset\*(R" in DBIx::Class::ResultSet.
.SS "first"
.IX Subsection "first"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $value" 4
.el .IP "Return Value: \f(CW$value\fR" 4
.IX Item "Return Value: $value"
.PD
.PP
Resets the underlying resultset and returns the next value of the column in the
resultset (or \f(CW\*(C`undef\*(C'\fR if there is none).
.PP
Much like \*(L"first\*(R" in DBIx::Class::ResultSet but just returning the one value.
.SS "single"
.IX Subsection "single"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $value" 4
.el .IP "Return Value: \f(CW$value\fR" 4
.IX Item "Return Value: $value"
.PD
.PP
Much like \*(L"single\*(R" in DBIx::Class::ResultSet fetches one and only one column
value using the cursor directly. If additional rows are present a warning
is issued before discarding the cursor.
.SS "min"
.IX Subsection "min"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $lowest_value" 4
.el .IP "Return Value: \f(CW$lowest_value\fR" 4
.IX Item "Return Value: $lowest_value"
.PD
.PP
.Vb 1
\&  my $first_year = $year_col\->min();
.Ve
.PP
Wrapper for \->func. Returns the lowest value of the column in the
resultset (or \f(CW\*(C`undef\*(C'\fR if there are none).
.SS "min_rs"
.IX Subsection "min_rs"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $resultset" 4
.el .IP "Return Value: \f(CW$resultset\fR" 4
.IX Item "Return Value: $resultset"
.PD
.PP
.Vb 1
\&  my $rs = $year_col\->min_rs();
.Ve
.PP
Wrapper for \->func_rs for function \s-1\fIMIN\s0()\fR.
.SS "max"
.IX Subsection "max"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $highest_value" 4
.el .IP "Return Value: \f(CW$highest_value\fR" 4
.IX Item "Return Value: $highest_value"
.PD
.PP
.Vb 1
\&  my $last_year = $year_col\->max();
.Ve
.PP
Wrapper for \->func. Returns the highest value of the column in the
resultset (or \f(CW\*(C`undef\*(C'\fR if there are none).
.SS "max_rs"
.IX Subsection "max_rs"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $resultset" 4
.el .IP "Return Value: \f(CW$resultset\fR" 4
.IX Item "Return Value: $resultset"
.PD
.PP
.Vb 1
\&  my $rs = $year_col\->max_rs();
.Ve
.PP
Wrapper for \->func_rs for function \s-1\fIMAX\s0()\fR.
.SS "sum"
.IX Subsection "sum"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $sum_of_values" 4
.el .IP "Return Value: \f(CW$sum_of_values\fR" 4
.IX Item "Return Value: $sum_of_values"
.PD
.PP
.Vb 1
\&  my $total = $prices_col\->sum();
.Ve
.PP
Wrapper for \->func. Returns the sum of all the values in the column of
the resultset. Use on varchar-like columns at your own risk.
.SS "sum_rs"
.IX Subsection "sum_rs"
.IP "Arguments: none" 4
.IX Item "Arguments: none"
.PD 0
.ie n .IP "Return Value: $resultset" 4
.el .IP "Return Value: \f(CW$resultset\fR" 4
.IX Item "Return Value: $resultset"
.PD
.PP
.Vb 1
\&  my $rs = $year_col\->sum_rs();
.Ve
.PP
Wrapper for \->func_rs for function \s-1\fISUM\s0()\fR.
.SS "func"
.IX Subsection "func"
.ie n .IP "Arguments: $function" 4
.el .IP "Arguments: \f(CW$function\fR" 4
.IX Item "Arguments: $function"
.PD 0
.ie n .IP "Return Value: $function_return_value" 4
.el .IP "Return Value: \f(CW$function_return_value\fR" 4
.IX Item "Return Value: $function_return_value"
.PD
.PP
.Vb 2
\&  $rs = $schema\->resultset("CD")\->search({});
\&  $length = $rs\->get_column(\*(Aqtitle\*(Aq)\->func(\*(AqLENGTH\*(Aq);
.Ve
.PP
Runs a query using the function on the column and returns the
value. Produces the following \s-1SQL:\s0
.PP
.Vb 1
\&  SELECT LENGTH( title ) FROM cd me
.Ve
.SS "func_rs"
.IX Subsection "func_rs"
.ie n .IP "Arguments: $function" 4
.el .IP "Arguments: \f(CW$function\fR" 4
.IX Item "Arguments: $function"
.PD 0
.ie n .IP "Return Value: $resultset" 4
.el .IP "Return Value: \f(CW$resultset\fR" 4
.IX Item "Return Value: $resultset"
.PD
.PP
Creates the resultset that \f(CW\*(C`func()\*(C'\fR uses to run its query.
.SS "throw_exception"
.IX Subsection "throw_exception"
See \*(L"throw_exception\*(R" in DBIx::Class::Schema for details.
.SH "FURTHER QUESTIONS?"
.IX Header "FURTHER QUESTIONS?"
Check the list of additional \s-1DBIC\s0 resources.
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
This module is free software copyright
by the DBIx::Class (\s-1DBIC\s0) authors. You can
redistribute it and/or modify it under the same terms as the
DBIx::Class library.