您应该考虑一些棘手的sql，如下所示：

select dsd
from (select 'potato' as dsd) ss
where (select 'I am spiderman and I have a potato') rlike dsd;

例子：

mysql> select dsd from (select 'potato' as dsd) ss where (select 'I am spiderman and I have a potato') rlike dsd;
+--------+
| dsd    |
+--------+
| potato |
+--------+

你只需要 INSTR 功能：

--sample data creation
create table tbl(id int, str varchar(50));
insert into tbl values (1, 'spiderman');
insert into tbl values (2, 'potatoes');

select * from tbl
where instr('I am spiderman and I have a potato', str) > 0;

select * from tbl
where instr('I am a spider and I like potatoes', str) > 0;

见mysql INSTR() 函数以供参考。