如何用两个表的条件??
有两个表:如下
tableA tableB
---------------------- ----------------------------
columnA columnB columnC columnD
970 c1 one c1
097 c1 two c1
0 c2 three c2
46 c2 four c2
用了的sql语句:
select columnA,columnC
from tableA,tableB
where columnB=columnD
and columnC='one'
结果:
970 one
097 one
我想要的结果是:
970 one
应该如何写呢?