sql - Oracle SQL：查找重复行

Question

我有下表

itemId   Name   PartNum    Price
 1      apple    123       0.99
 2      orange   234       0.5
 3      apple    123       0.99

我想找到重复的行。它应该输出

ItemId  Name  PartNum  Price
 1     apple    123    0.99
 3     apple    123    0.99

怎么做？？？？？？？

Answer 1

基本上有几种方法可以将表连接到自身。common table expression这是使用带有功能的一种解决方案rank()：

with cte as (
  select itemId, 
    name, 
    partnum, 
    price, 
    rank() over (order by name, partnum, price) rnk
  from yourtable
  ) 
select distinct c.* 
from cte c
  join cte c2 on c.rnk = c2.rnk and c.itemid != c2.itemid

SQL 小提琴演示

---

这是另一种方法：

select distinct y.* 
from yourtable y
  join yourtable y2 on 
      y.name = y2.name and 
      y.partnum = y2.partnum and 
      y.price = y2.price and 
      y.itemid != y2.itemid

更多小提琴

Answer 2

现在我明白了，你可以这样做：

select * from yourTable where name in (
  select name from (
    SELECT Name, PartNum, Price, count(ItemId) qtd
    FROM yourTable 
    group by Name, PartNum, Price,) 
  where qtd>1)

Answer 3

Claudio 的答案非常接近，但要根据重复项的数量过滤结果，您需要添加一个 having 子句：

select name, partnum, price
from yourTable 
group by name, partnum, price 
having count(itemId) > 1

Answer 4

这是另一种方法：

查询：

select *
from Table1
where Name||','||PartNum in (
    select Name||','||PartNum
    from Table1
    group by Name, PartNum
    having count(*) > 1)

结果：

| ITEMID |  NAME | PARTNUM | PRICE |
|--------|-------|---------|-------|
|      1 | apple |     123 |  0.99 |
|      3 | apple |     123 |  0.99 |

Answer 5

This is another alternative

SELECT t1.itemId, t1.name, t1.partNum, t1.price
FROM table1 t1
INNER JOIN (SELECT name, partNum, price, COUNT(*) AS count
            FROM table1
            GROUP BY name, partNum, price
            HAVING COUNT(*) > 1
           ) dt ON t1.name = dt.name and t1.partNum = dt.partNum 
                and t1.price = dt.price
ORDER BY t1.itemId

Check it on SQL FIDDLE

Answer 6

这是fiddle的另一种方法。这使用了解析函数count(*)

select itemid,name,partnum,price
from (
select itemid,
       name,
       partnum,
       price,
       count(*) over (partition by partnum
                      order by price) as part_count
from yourtable
  )
where part_count >1