你可以用 group by 以及 having ```
SELECT COUNTY, CITY, ZIP
FROM MoratoriumLocations
WHERE MoratoriumID=20
GROUP BY COUNTY, CITY, ZIP
HAVING COUNT(1) >1
ORDER BY County

如果您想获得完整的行详细信息，可以将子查询与 `group by` 以及 `having` 声明

SELECT x.*
FROM MoratoriumLocations x
INNER JOIN(
SELECT COUNTY, CITY, ZIP
FROM MoratoriumLocations
WHERE MoratoriumID=20
GROUP BY COUNTY, CITY, ZIP
HAVING COUNT(1) >1
) dups ON dups.County = x.County
AND dups.City = x.City
AND dups.Zip = x.Zip

有关如何查找DUP，请参见preben的答案。
为了避免DUP，请考虑创建一个唯一索引。

我建议窗口功能：

SELECT ml.*
FROM (SELECT ml.*, COUNT(*) OVER (PARTITION BY County, City, Zip) as cnt
      FROM MoratoriumLocations ml
      WHERE MoratoriumID = 20
     ) ml
ORDER BY cnt DESC, County, City, Zip;

这将显示包含重复项的完整行，这可以帮助您更好地理解它们。