如何解决这个数据库编程问题？

我是新手，希望大家多多指点。
我想要实现的功能如下：
怎样连接数据库，并把给定的一个数值$t与数据库中$table表第一个字段的值$a和第二个字段的值$b进行对比，如果数值$t在$a和$b之间，则输出$table表第三个字段的值$c。

这个过程怎样完成？希望能详细点，不胜感激！

就告诉我如何就连接数据库，如何操作表就可以了，谢谢！

perldoc DBI

#!/usr/bin/perl
# Fig. 15.18: fig15_18.pl
# Program to query a database and display the contents in a table  

use warnings;
use strict;
use DBI;
use DBD::ODBC;

my $dbh = DBI->connect( "DBI:ODBC:employeeDB", "", "" ) or
   die( "Could not make connection to database: $DBI::errstr" );

my $sth = $dbh->prepare( q{ SELECT * FROM employee } ) or
   die( "Cannot prepare statement: ", $dbh->errstr(), "\n" );
     
my $rc = $sth->execute() or
   die( "Cannot execute statement: ", $sth->errstr(), "\n" );

my @array;

while ( @array = $sth->fetchrow_array() ) {
   write();
}

# Check to see if fetch terminated early
warn( $DBI::errstr ) if $DBI::err;

$sth->finish();
$dbh->disconnect();

format STDOUT =  
@<<<<<<@<<<<<<<<<@<<<<<<<<<<@<<<<<@<<<<<<<<<<<<
$array[ 0 ], $array[ 1 ], $array[ 2 ], $array[ 3 ], $array[ 4 ]
.


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while ( @array = $sth->fetchrow_array() ) {
   write();
}
write()是不是把记录写进内存？