DBI202Xuất hiện trong 1 đề thi
You have a column named TelephoneNumber that stores numbers as varchar(20). You need to write a query that returns the first three characters of a telephone number. Which expression should you use?
Các lựa chọn
ACHARINDEX('[0-9][0-9][0-9]', TelephoneNumber, 3)
BSUBSTRING(TelephoneNumber, 3, 1)
CSUBSTRING(TelephoneNumber, 3, 3)
DLEFT(TelephoneNumber, 3)