Question

SELECT
    TreatableComments, Category, Comment_Date, Comment_Time, Reported_Url
FROM
    TestData.dbo.CXA
GROUP BY 
    TreatableComments, Category, Comment_Date, Comment_time, Reported_Url
HAVING 
    COUNT(TreatableComments) > 1 AND Category IS NULL

Answer 1

看到您的问题没有数据库系统标签，我想在SQL Server（2016）中快速尝试一下：

--Data
DECLARE @table TABLE (TreatableComments VARCHAR(50), Category VARCHAR(50), CommentDate DATE, Reported_Url VARCHAR(50));
INSERT INTO @table
SELECT 'Stuff', 'Category 1', '20180101', 'stackoverflow.com'
UNION ALL
SELECT 'More Stuff', 'Category 2', '20180103', 'stackoverflow.com'
UNION ALL
SELECT 'Same', NULL, '20180101', 'stackoverflow.com'
UNION ALL
SELECT 'Same', NULL, '20180101', 'stackoverflow.com';

--Query
SELECT
    TreatableComments,
    Category,
    CommentDate,
    Reported_Url
FROM
    @table
GROUP BY
    TreatableComments,
    Category,
    CommentDate,
    Reported_Url
HAVING
    COUNT(TreatableComments) > 1
    AND Category IS NULL;

当我运行它时，即它给了我一行：

TreatableComments   Category    CommentDate Reported_Url
Same                NULL        2018-01-01  stackoverflow.com

因此，这意味着您的数据看起来与我的数据完全不同，并且没有任何带有NULL类别的重复项，或者您使用的数据库在这方面与SQL Server不同，因此tbh似乎不太可能，因为这是非常普通的SQL。

看到您真正想要的与您最初提出的问题完全不同，这是一个新答案：

--Data
DECLARE @table TABLE (TreatableComments VARCHAR(50), Category VARCHAR(50), CommentDate DATE, Reported_Url VARCHAR(50));
INSERT INTO @table
SELECT 'Stuff', 'Category 1', '20180101', 'stackoverflow.com'
UNION ALL
SELECT 'More Stuff', 'Category 2', '20180103', 'stackoverflow.com'
UNION ALL
SELECT 'Same', 'A', '20180101', 'stackoverflow.com'
UNION ALL
SELECT 'Same', NULL, '20180101', 'stackoverflow.com';

--Query
SELECT
    t.*
FROM
    @table t
    INNER JOIN (
    SELECT
        TreatableComments,
        CommentDate,
        Reported_Url
    FROM
        @table
    GROUP BY
        TreatableComments,
        CommentDate,
        Reported_Url
    HAVING
        COUNT(TreatableComments) > 1) d ON d.TreatableComments = t.TreatableComments AND d.CommentDate = t.CommentDate AND t.Reported_Url = d.Reported_Url
WHERE
    t.Category IS NULL;

这可以通过查找重复的案例，然后再联接回主表并仅选择类别为NULL的行来实现。

新结果是：

TreatableComments   Category    CommentDate Reported_Url
Same            NULL            2018-01-01  stackoverflow.com

查询以在重复行且列包含NULL值的条件下获取重复行。

1 个答案: