関連ワード:  sql first 3 characters of string    sql first 3 letters of string    sql get first 3 characters of string    sql remove first 3 characters of string    sql get first 3 letters of string    oracle sql get first 3 characters of string    sql select first 3 characters from string    proc sql first 3 character from string    sql first 3 characters    sql substring first 3 characters