Bulk update an address column where the address was duplicated with a delimiter separating the duplicate?
You can do this by using the CHARINDEX() function to find the position of the semicolon, coupled with SUBSTRING() to update the field with the data prior to the semicolon.

UPDATE test_table SET addr=SUBSTRING(addr, 0, CHARINDEX(';',addr))


If there are any legitimate semicolons in the data then it will of course remove some of the address, so please check the data first to ensure there is only one semicolon in each record.