Did you really mean to reply to my post? It seems you ignored everything I said.

This sequence of statements can be easier:
my $query = $dbh->prepare("SELECT * FROM finalLevel3 WHERE id='$ID'");

Just adding quotes around the contents of $ID doesn't properly convert it from arbitrary text into an SQL string literal. It's an bug or injection attack waiting to happen. It's also very inefficient. You're compiling the query over and over and over again. The following is a whole world better: 

# Outside of loop
my $sth = $dbh->prepare("SELECT * FROM finalLevel3 WHERE id=?");

$sth->execute($ID);

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I would think that since you are iterating over clusters, that something like this would be more clear:

If you look closely, you'll notice he's actually iterating over the cluster indexes, so the following would be even better: 

for my $i (0..$#$clusters)

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So when do you need the extra {}? You need this when dereferencing an indexed expression, but not a non-indexed one.

@{ foo() } would also need it. The correct answer would be "Pretty much anything other than a variable name" or maybe even "Everything other than a variable name".

In reply to Re^3: perl, mysql: "fetchrow_array failed: fetch() without execute()" by ikegami
in thread perl, mysql: "fetchrow_array failed: fetch() without execute()" by gojira

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