MYSQL запросы

Найти одинаковые строки

select a.stb1, a.stb2, a.stb3, a.stb4, COUNT(*) AS col1 
from table1 a 
where a.stb1> 0 and a.ctb2 >= 1 
GROUP BY a.stb1, a.stb2, a.stb3, a.stb4 DESC HAVING COUNT(*) > 1 
ORDER BY col1; 

блок where - не обязателен.