Why is MySQL giving me a syntax error? - mysql

Question

so I am pretty much a big newbie in coding and I am kinda learning by Trial and error, this time I am trying to work with a DB with Perl, actually it works well when I just use 3 table headers (Terminal, Zeitstempel, Ergebnisnummer) but when I try to add more headers (Ergebnistext, Transart, Belegnummer, Trace, Betrag, Kartenart, Kartennummer, Entrymode) it is always giving me a Syntax-error and I checked for half an hour but couldnt find the error. If anyone knows why I would appreciate your help! this part of my code Looks like this:
foreach $file (#file)
{
$currentfile = "$currentdir\\$file";
open(zloop, "<", $currentfile) or die "Failed to open file: $!\n";
while ( <zloop> ) {
my %row;
chomp;
#row{#headers} = split /;/;
my $tid = $row{'tid'};
my $zeit = $row{'zeit'};
my $ergebnisnummer = $row{'ergebnisnummer'};
my $ergebnistext = $row{'ergebnistext'};
my $transart = $row{'transart'};
my $belegnummer = $row{'belegnummer'};
my $trace = $row{'trace'};
my $betrag = $row{'betrag'};
my $kartenart = $row{'kartenart'};
my $kartennummer = $row{'kartennummer'};
my $entrymode = $row{'entrymode'};
my $sth = $dbh->prepare("INSERT INTO `teso`( Terminal, Zeitstempel, Ergebnisnummer, Ergebnistext, Transart, Belegnummer, Trace, Betrag, Kartenart, Kartennummer, Entrymode )
values ( $tid, $zeit, $ergebnisnummer, $ergebnistext, $transart, $belegnummer, $trace, $betrag, $kartenart, $kartennummer, $entrymode )");
$sth->execute() or die $DBI::errstr;
$sth->finish();
i didnt Change the variable names to english because maybe they are causing the Syntax error. This is the error message:
DBD::mysql::st execute failed: You have an error in your SQL syntax;
check the m anual that corresponds to your MySQL server version for
the right syntax to use near '' )' at line 2 at
C:\Users\Desktop\findlogstamp\sqlneu.pl lin e 50, line 1. You
have an error in your SQL syntax; check the manual that corresponds to
your MySQL server version for the right syntax to use near '' )' at
line 2 at C:\User s\Desktop\findlogstamp\sqlneu.pl line 50,
line 1.

Answer 1

You are possibly getting quotation errors arising from passing your variables in as a string. You should instead use placeholders.
Try doing something like this instead:
my $sth = $dbh->prepare('INSERT INTO `teso`( Terminal, Zeitstempel, Ergebnisnummer, Ergebnistext,
Transart, Belegnummer, `Trace`, Betrag, Kartenart, Kartennummer, Entrymode )
values ( ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ? )');
$sth->execute($tid, $zeit, $ergebnisnummer, $ergebnistext,
$transart, $belegnummer, $trace, $betrag, $kartenart,
$kartennummer, $entrymode) or die $DBI::errstr;
I've also included mwp's answer too.
It is also worth time reading Borodins Answer for a more thorough way to approach placeholders and SQL inside perl.

Answer 2

I believe "trace" is a reserved word in MySQL. Try adding backticks around the column name(s).

Answer 3

Values in an SQL expression must be quoted correctly. Simple numeric values don't need quoting, and I imagine the first three columns that you used -- terminal ID, timestamp, and result number -- are all numbers, which is why they worked without quotes
The DBI module provides functions database handle method quote which will do this for you (as well as quote_identifier which does the same thing for identifiers, such as table and column names). However it is always much safer to prepare an SQL statement with placeholders instead of trying to interpolate the values into the string yourself. Then the actual values can be provided in the execute call, wehen DBI will implicitly call $dbh->quote on all of the values before inserting them into the statement
It is also best to prepare a statement just once, as the handle may then be used repeatedly. And there is no need to extract a series of scalar variables from your %row hash -- a hash slice can be used to fetch the correct fields straight from the hash into the execute call. It is best, however, to keep a list of the field names in an array as you have done with #headers; in fact your #headers may be the same as my #items, in which case there is no need to define both
I have used a here document for the SQL string. If you want to do the same thing then be careful that there must be no white space either before or after the end tag END_SQL otherwise it won't be found
Note that I've used join together with the list repetition operator x to produce exactly the right number of question mark placeholders in the QSL. It's much safer to do things this way so as to avoid miscounting, and to allow the number of fields to be changed without altering the SQL statement. You can print "$sql\n" to see the SQL that has been built if you wish
I hope this helps
my #items = qw/
tid zeit ergebnisnummer ergebnistext transart
belegnummer trace betrag kartenart kartennummer entrymode
/;
my $sql = sprintf <<END_SQL, join ', ', ('?') x #items;
INSERT INTO teso (
Terminal, Zeitstempel, Ergebnisnummer, Ergebnistext, Transart,
Belegnummer, Trace, Betrag, Kartenart, Kartennummer, Entrymode
)
VALUES (%s)
END_SQL
my $insert = $dbh->prepare($sql);
for my $file ( #file ) {
my $current_file = "$currentdir\\$file";
open my $fh, '<', $current_file or die qq{Unable to open "$current_file" for input: $!};
while ( <$fh> ) {
my %row;
#row{#headers} = split /;/;
$insert->execute(#row{#items}) or die $sth->errstr;
}
}

Answer 4

I think, error is because backticks around teso is interpolated by perl.
Anyway, interpolating values into a query string is a really bad idea.
You can replace quotation marks around your query with a single quotes (to eliminate undesired interpolation) and replace values to be inserted with a placeholders. Then you should pass actual values to execute() method. Like this:
my $sth = $dbh->prepare('INSERT INTO teso( Terminal, Zeitstempel, Ergebnisnummer, Ergebnistext, Transart, Belegnummer, Trace, Betrag, Kartenart, Kartennummer, Entrymode )
values ( ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ? )');
$sth->execute($tid, $zeit, $ergebnisnummer, $ergebnistext, $transart, $belegnummer, $trace, $betrag, $kartenart, $kartennummer, $entrymode) or die $DBI::errstr;
$sth->finish();
or, if you wish to insert just a single row, you can replace all this with a single do():
$dbh->do('INSERT INTO teso( Terminal, Zeitstempel, Ergebnisnummer, Ergebnistext, Transart, Belegnummer, Trace, Betrag, Kartenart, Kartennummer, Entrymode ) values ( ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ? )', undef,
$tid, $zeit, $ergebnisnummer, $ergebnistext, $transart, $belegnummer, $trace, $betrag, $kartenart, $kartennummer, $entrymode ) or die $DBI::errstr;