I've pointed you to DBD::CSV's "CREATE TABLE AS SELECT" syntax in several other threads but you don't seem to have seen it, so here goes again: You can create a new CSV file from one or more old CSV files in a single step with this kind of syntax: 
$dbh->do("
   CREATE TABLE new_csv_file
      AS SELECT (columns)
           FROM old_csv_file1 
           JOIN old_csv_file2
");

[download]
The JOIN may be natural, inner, outer, left, right, or full. You can use table and column aliases, supply a WHERE clause, etc. This creates the new CSV file from the data result set you specify in the SELECT clause. You don't need to put the results into an array or hash or any other structure, just go from CSV file to CSV file using SQL.

update : Make sure you have the latest version of SQL::Statement, DBD::CSV's SQL engine, the syntax is supported in SQL::Statement version 1.14 and later.

In reply to Re: Process and combine two CSV files into one by jZed
in thread Process and combine two CSV files into one by DrAxeman

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