问一个SQL查询问题

[stan23]

1."select c2 from table1 where c1=1"
2."select c2 from table1 where c1=2"
想看看1，2的结果中有没有相同的数据，怎样用一条SQL语句做到呢？

[helloyou0]

select count(*) from
table1 a, table1 b
where a.c2=b.c2 and a.c1=1 and b.c1=2;

[懒得去死]

select count(*) from
table1 a, table1 b
where a.c2=b.c2 and a.c1=1 and b.c1=2;

[stan23]

谢谢两位，已经解决！