select sum(zd) as sum_zat from BD WHERE det=ALLTRIM(thisform.text1.Value) INTO CURSOR ksumzat

AND not DELETED()

Create Cursor test (f1 i)
Insert into test values (10)
Insert into test values (10)
Insert into test values (10)
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Delete

Set Deleted Off
Select Sum(f1) from test

Set Deleted On
Select Sum(f1) from test

select sum(zd) as sum_zat from BD WHERE det=ALLTRIM(thisform.text1.Value) AND not DELETED() INTO CURSOR ksumzat

set delet on
select sum(zd) as sum_zat from BD WHERE det=ALLTRIM(thisform.text1.Value) INTO CURSOR ksumzat