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Online Sandbox for SQL and PHP: Write, Run, Test, and Share SQL Queries and PHP Code
<?php
echo 'aa' === strtoupper('aa') ? 'yes' : 'no';
echo PHP_EOL;
echo 'АБ' === mb_strtoupper('АБ') ? 'yes' : 'no';
echo PHP_EOL;
echo 'АБв' === mb_strtoupper('АБв') ? 'yes' : 'no';