Mssql err: Column 'dbo.History.Email' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause - tsql

Question

when executing this MSSQL statement it forces me to add the CASE WHEN field History.Email in the group by field, however I need to group only on a date field.
Any idea how this can be solved? (sql 2008)
SELECT TOP (100)
convert(varchar, VisitDate, 111) as Date,
SUM(AmountLoaded) AS Loaded,
CASE when History.Email is null then
SUM(AmountCash)
else SUM(AmountToPay)
end AS Total,
CASE when History.Email is null then
0
else SUM(AmountToPay)
end AS App,
SUM(AmountToPay) AS Consumed
FROM dbo.History
GROUP BY convert(varchar, VisitDate, 111)
order by 1 desc

Answer 1

When performing conditional aggregation you need to put the entire CASE expression in an aggregate, not just the expression(s) you want to aggregate:
SELECT TOP (100)
CONVERT(varchar(10), H.VisitDate, 111) AS [Date], --Always specify a length/precision/scale for your data types
SUM(H.AmountLoaded) AS Loaded,
SUM(CASE WHEN H.Email IS NULL THEN H.AmountCash ELSE H.AmountToPay END) AS Total,
SUM(CASE WHEN H..Email IS NULL THEN 0 ELSE H.AmountToPay END) AS App,
SUM(H.AmountToPay) AS Consumed
FROM dbo.History H
GROUP BY CONVERT(varchar(10), H.VisitDate, 111) --Always specify a length/precision/scale for your data types
ORDER BY [Date] DESC; --Be specific, don't use ordinal positions
Note, as well, I suggest not converting your column VisitDate to a varchar in your query. If you want to display the data in a specific format then that's something for your presentation layer to do, not the RDBMS. Fortunately, as style 111 is yyyy/MM/dd then the order of the data isn't affected. If, however, you want to simply truncate the time portion of your value, convert it to a date so that the value continues to remain strongly typed.

Answer 2

By definition any nonaggregate fields should be in the group by clause. You can write that as:
SELECT TOP (100)
convert(varchar, VisitDate, 111) as Date,
SUM(AmountLoaded) AS Loaded,
SUM(CASE when History.Email is null
then AmountCash
else AmountToPay end) AS Total,
SUM(CASE when History.Email is null
then 0
else AmountToPay
end) AS App,
SUM(AmountToPay) AS Consumed
FROM dbo.History
GROUP BY convert(varchar, VisitDate, 111)
order by 1 desc