> I am assigning a variable dynamically and using it in a query to
> fetch values from my database. Here is the pseudo code...
>
> ###########
> my $string ;
> my $q1 = "select * from bugs where target_milestone = ? and date
> between ? and ?;
> my $q2 = "select * from bugs where $string and target_milestone = ?
> and date between ? and ?;
>
> foreach my $q ($q1,$q2){
> $stmt = $dbh->prepare($q1) or die ""; #####$dbh already has a valid
> handle
> $stmt->execute() or die "";
>
> $string = "bug_id not in (1,2,3)"; #### 1,2,3 are eg. values which
> i get after process $q1 and i #use it in $q2
> }
>
> ##################################
>
> howver it happens that $string is not used in $q2 i.e. $q2 is executed
> without taking into account the newly assigned value to $string and
> instead using '';
>
> Is it that perl compiles the statement statement beforehand and never
> really substitutes it when foreach loop advances to use $q2.
No it doesn't compile the statement. The catch is that string
interpolation (the change from $varname to the value of the $varname
in doublequoted strings) happens at the place you specify the
doublequoted literal, not every time you used it:
#!perl
$x = 'original';
$string = "The x='$x'.";
$x = 'modified';
print $string;
If you want to change the value of the $q2 after it was assigned you
have to put a mark there and replace that mark once you have the
value you want to replace there. Something like
my $string ;
my $q1 = "select * from bugs where target_milestone = ? and date
between ? and ?;
my $q2 = "select * from bugs where ### and target_milestone = ? and
date between ? and ?;
foreach my $q_template ($q1,$q2){
(my $q = $q_template) =~ s/###/$string/g;
$stmt = $dbh->prepare($q1) or die "";
#####$dbh already has a valid handle
$stmt->execute() or die "";
$string = "bug_id not in (1,2,3)";
#### 1,2,3 are eg. values which i get after process $q1
# and i use it in $q2
}
HTH, Jenda
===== [EMAIL PROTECTED] === http://Jenda.Krynicky.cz =====
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