在Oracle数据库表中返回给定列的重复值及其出现次数的最简单SQL语句是什么?
例如:我有一个列为JOB_NUMBER的JOBS表。如何才能知道我是否有任何重复的JOB_NUMBERs，以及它们重复了多少次?
当前回答
如何:
SELECT <column>, count(*)
FROM <table>
GROUP BY <column> HAVING COUNT(*) > 1;
要回答上面的例子，它看起来像:
SELECT job_number, count(*)
FROM jobs
GROUP BY job_number HAVING COUNT(*) > 1;
其他回答
做
select count(j1.job_number), j1.job_number, j1.id, j2.id
from jobs j1 join jobs j2 on (j1.job_numer = j2.job_number)
where j1.id != j2.id
group by j1.job_number
将给出复制行的id。
你也可以尝试这样的方法在一个表中列出所有重复的值，比如reqitem
SELECT count(poid)
FROM poitem
WHERE poid = 50
AND rownum < any (SELECT count(*) FROM poitem WHERE poid = 50)
GROUP BY poid
MINUS
SELECT count(poid)
FROM poitem
WHERE poid in (50)
GROUP BY poid
HAVING count(poid) > 1;
我知道这是一个老帖子，但这可能会帮助一些人。
如果你需要打印表的其他列，同时检查重复使用如下:
select * from table where column_name in
(select ing.column_name from table ing group by ing.column_name having count(*) > 1)
order by column_name desc;
如果需要，还可以在where子句中添加一些额外的过滤器。
下面是一个SQL请求:
select column_name, count(1)
from table
group by column_name
having count (column_name) > 1;
如果您不需要知道重复的实际数量，则甚至不需要在返回列中显示计数。如。
SELECT column_name
FROM table
GROUP BY column_name
HAVING COUNT(*) > 1
