Oracle:-- 没有直接的函数.CREATE table test (a varchar(100));insert into test values('test.abc.oracle.com.cn');-- 获取第一个.SELECTSUBSTR(a, 1, INSTR (a, '.') -1 ) AS ResultFROMtest;RESULT---------testSQLServer-- 没有直接的函数.CREATE table test (a varchar(100));insert into test values('test.a...