SQL数据库中有表A,在表A中有列名为B的列,B列中的数据为01到36。如何编写SQL语句查询B列中01到36各数的出现次数?
SQL语句select count(B) from A where B = 01可以查询到01的出现次数。怎样才能使用一个语句就能循环查询到01到36的出现次数?
select countB)from A group by B order by B
SQL语句就可以做了,例检索表格aaa,添加一列“re_num”,显示a列值重复的次数,
次数为表格按a列分组计算记录数:
select a,count(a) as 're_num' from aaa group by a,
select a1.a2.re_num from
aaa a1
join
(select a,count(a) as 're_num' from aaa group by a) a2
on a1.a = a2.a;
select sum(datac.COUNT_VALUE)
from T_JL_COUNT_DATA datac
, T_JL_XC_RESULT a
where datac.COUNT_NO=45 and a.id=datac.RESULT_ID。