Look at this image,

connection 57 has this query

update reque_pa with (updlock) set MINIMO = 2 WHERE CEREQ = 1

connection 58 has this query

SELECT * FROM Reque_pa WHERE CEREQ = 2

To complete query 2, query 1 has to finish (i put a wait.... to test it)

lock the locks in image, connection 57 makes a row lock!!! for every row I have in the table,

resouce description

1:1702673:0 (this is the row I am updating in query 1)

1:1702673:1

1:1702673:2

1:1702673:3

1:1702673:4

I can't explain why sql behaves this way..

Hope this helps!