infinite loop in an update statement

[Fabrice Chapuis <fabrice636861@xxxxxxxxx>]

Hi,

table a and b are empty, this query does not return. It seems we enter in infinite loop.

why this update does not return instantly?

UPDATE table_a a                                                

 SET col1 = (SELECT MIN(b.col1)                               

                    FROM table_b b                                      

                    WHERE b.col2 = a.col2)

Regards,

Fabrice