先启动转义符 set escape on select B from A where b like '%\_a%' escape '\';
select B from A where b like '%\_a%' escape '\'
SQL> create table a (b varchar2(10));Table createdSQL> insert into a values('_a');1 row insertedSQL> select B from A where instr(b,'_a')>0;B ---------- _a
set escape on
select B from A where b like '%\_a%' escape '\';
----------
_a