SQRT

SQRT(X)

Devuelve la raíz cuadrada no negativa de X:

mysql> SELECT SQRT(4);
+----------+
| SQRT(4)  |
+----------+
| 2.000000 |
+----------+
1 row in set (0.00 sec)

mysql> SELECT SQRT(20);
+----------+
| SQRT(20) |
+----------+
| 4.472136 |
+----------+
1 row in set (0.00 sec)