SELECT  ID,
        sentence  
FROM    texts
WHERE   sentence LIKE '% $query %'
##</code><code>##

SELECT  ID,
        sentence  
FROM    texts
WHERE   sentence LIKE '% $query %'
   OR   sentence LIKE '$query %'
   OR   sentence LIKE '% $query'
   OR   sentence = '$query'
##</code><code>##

SELECT  ID,
        sentence  
FROM    texts
WHERE   sentence LIKE '%$query%'
##</code><code>##

my $sth = $dbh->prepare(<<'EOSQL');
SELECT  ID,
        sentence  
FROM    texts
WHERE   sentence LIKE ? ESCAPE ?
EOSQL
$sth->execute("%$query%", '\\');
my $results = [];
while (my @row = $sth->fetchrow_array) {
    push @$results, \@row if $row[1] =~ /\b\Q$query\E\b/;
}