select teacherid , teachername , (select max(1) from likes where teacherid=t.teacherid) ,teacherage from teachers t
SELECT A.*,CONCAT(A.teachername,IF(B.teacherid IS NULL,0,1)) FROM teachers A LEFT JOIN likes B ON A.teacherid=B.teacherid
--不得不说和楼上的斑竹的,,,, select te.tid, CONCAT(teName,"(",IF(li.lid is not null,1,0),")") teName_, te.tage from teachers te left join likes li on te.tid = li.tid order by te.tid--或者(很明显上一个简洁,) select temp.tid,concat(temp.teName,"(",IF(lid is not NULL,1,0),")") teName,temp.tage,temp.lid from ( select te.tid,te.teName,te.tage,li.lid from teachers te left join likes li on te.tid = li.tid order by te.tid ) temp;
SELECT A.teacherid,CONCAT(A.teachername,case when B.teacherid IS NULL then 0 else 1 end)teachername,A.teacherage FROM teachers A LEFT JOIN likes B ON A.teacherid=B.teacherid
(select max(1) from likes where teacherid=t.teacherid)
,teacherage
from teachers t
LEFT JOIN likes B
ON A.teacherid=B.teacherid
--不得不说和楼上的斑竹的,,,,
select te.tid,
CONCAT(teName,"(",IF(li.lid is not null,1,0),")") teName_,
te.tage
from teachers te
left join likes li
on te.tid = li.tid
order by te.tid--或者(很明显上一个简洁,)
select temp.tid,concat(temp.teName,"(",IF(lid is not NULL,1,0),")") teName,temp.tage,temp.lid from
(
select te.tid,te.teName,te.tage,li.lid from teachers te left join likes li on te.tid = li.tid order by te.tid
) temp;
LEFT JOIN likes B
ON A.teacherid=B.teacherid