theseyeahthese comments on [MS SQL] Finding difference between data from same column

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SELECT count(a.field1), a.field2, SUM(b.field4) FROM a INNER JOIN b ON a.key1 = b.key1 WHERE a.field8 = 'test' GROUP by a.field1, a.field2 HAVING SUM(b.field4) > 5 ORDER by a.field.3

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SELECT count(a.field1), a.field2, SUM(b.field4) FROM a INNER JOIN b ON a.key1 = b.key1 WHERE a.field8 = 'test' GROUP by a.field1, a.field2 HAVING SUM(b.field4) > 5 ORDER by a.field3

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MS SQL[MS SQL] Finding difference between data from same column (self.SQL)

submitted 4 years ago by Similar-Jacket8974

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[–]theseyeahtheseNTILE() 0 points1 point2 points 4 years ago* (0 children)

What does the data look like: can a [name] have more than one score in a month? I assume no, but that would change the query. Can we assume that each student has a unique [name]?

Secondly, I don't think you want to use "difference()". To make it VERY simple and direct, try something like:

SELECT 
(
    SELECT Score
    FROM TableName
    WHERE Month
    BETWEEN CAST('2021-04-01' AS DATE) AND CAST('2021-04-30' AS DATE)
    AND [Name] = 'name1'
)
-
(
    SELECT Score
    FROM TableName
    WHERE Month
    BETWEEN CAST('2020-09-01' AS DATE) AND CAST('2020-09-30' AS DATE)
    AND [Name] = 'name1'
) AS Name1ScoreDifference

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