SELECT SINGLE weird behaviour

Hi Experts,

I have written the following query to pick up the address no. In case, there are multiple entries found in table ADRC according to my WHERE clause condition, the query returns the first address no out of those multiple address nos in one system 'A' whereas it returns the last address no. in similar situation in a different system B.

SELECT SINGLE addrnumber

name1

sort1

street

house_num1

city1

region

post_code1

INTO wa_customers

FROM adrc

WHERE sort2 EQ 'ABC'

AND addr_group EQ 'XY'.

Any idea why the same query is behaving differently in two system?

Thanks.