sql - 在列表中显示重复数据

Question

目标：
显示重复数据，在表格​​测试中，应删除。
但是，如果有两个重复数据，例如“3412 New York”。测试表中应仅显示 1 行。

问题：
不知道怎么做。请记住，此表可以是一百万行。

All data from the list

table testing
Region          Category    Energy
----------------------------------
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
3125 New Jersey drink       4
3125 New Jersey drink       4
3125 New Jersey drink       4
3125 New Jersey drink       4
3125 New Jersey drink       4
3412 New York   food        3
3412 New York   food        3
3412 Washington coke        7
3412 california chips       20
3412 california chips       20
3412 california chips       20
3412 california chips       20





Requested result that should display data in table testing
Table testing
Region          Category    Energy
----------------------------------
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
1235 Delaware   candy       5
3125 New Jersey drink       4
3125 New Jersey drink       4
3125 New Jersey drink       4
3125 New Jersey drink       4
3412 New York   food        3
3412 california chips       20
3412 california chips       20
3412 california chips       20

Answer 1

查看结果

SELECT
    Region, Category, Energy
FROM
    (
    SELECT
       Region, Category, Energy,
       ROW_NUMBER() OVER (PARTITION BY Region, Category, Energy ORDER BY Region) AS rn
    FROm
       MyTable
    ) X
WHERE
   X.rn > 1

Answer 2

因为您没有主键，所以您可以使用 group by 或 distinct 重新生成表：

select distinct Region, Category, Energy
into newt
from t

这将使您不必识别重复项，然后再次弄清楚如何删除这些行。