SQL sum with condition - sql

I currently have a large SQL statement which i add the following line to in order to get the total cash for each transaction ID (which are unique):
select sum(cash) from Table a where a.branch = p.branch
and a.transID = p.transID) TotalCash
and i now need to do the same but only total the cash values that have a valuedate within the last month, so i have something like this:
select sum(CASE ValueDate WHEN > #startMonthDate THEN cash ELSE NULL END)
from Table a where a.branch = p.branch and a.transID = p.transID) TotalMonthCash
Sorry that I dont have the whole statement, but it is really long and specific to the context of the stored procedure but was hoping someone would know what i mean?

Try this instead:
SUM(CASE WHEN ValueDate > #startMonthDate THEN cash ELSE 0 END)
Explanation
Your CASE expression has incorrect syntax. It seems you are confusing the simple CASE expression syntax with the searched CASE expression syntax. See the documentation for CASE:
The CASE expression has two formats:
The simple CASE expression compares an expression to a set of simple expressions to determine the result.
The searched CASE expression evaluates a set of Boolean expressions to determine the result.
You want the searched CASE expression syntax:
CASE
WHEN Boolean_expression THEN result_expression [ ...n ]
[ ELSE else_result_expression ]
END
As a side note, if performance is an issue you may find that this expression runs more quickly if you rewrite using a JOIN and GROUP BY instead of using a dependent subquery.

Try moving ValueDate:
select sum(CASE
WHEN ValueDate > #startMonthDate THEN cash
ELSE 0
END)
from Table a
where a.branch = p.branch
and a.transID = p.transID
(reformatted for clarity)
You might also consider using '0' instead of NULL, as you are doing a sum. It works correctly both ways, but is maybe more indicitive of what your intentions are.

With condition HAVING you will eliminate data with cash not ultrapass 0 if you want, generating more efficiency
in your query.
SELECT SUM(cash) AS money FROM Table t1, Table2 t2 WHERE t1.branch = t2.branch
AND t1.transID = t2.transID
AND ValueDate > #startMonthDate HAVING money > 0;

Related

using case statement in a where clause

Hello I am missing something because my code errors.
select * from ##ScheduleDetail SD
left join ##HolidayFilterTbl HF on SD.Scheduledate = HF.Testdate
where (ScheduleDate = testdate)
and
(Case
when HF.IsHoliday = 1 then (overtime = 1 and makeup = 0)
else
(overtime = 0 and Makeup = 0)
end
)
and
DOW = 5
order by ActivityStartTime
I've attempted several combinations and each one errors at either the first equal sign or the second. What am I missing?
The branches of a case expression can only return values, not additional expressions to be evaluated in the where condition. You could, however, simulate this behavior with the and and or logical operators:
select *
from ##ScheduleDetail SD
left join ##HolidayFilterTbl HF on SD.Scheduledate = HF.Testdate
where (ScheduleDate = testdate) and
((HF.IsHoliday = 1 and overtime = 1 and makeup = 0) or
(overtime = 0 and Makeup = 0)) and
DOW = 5
order by ActivityStartTime
Note that you have makeup = 0 on both branches of the case expression in the question (or both sides of the or in the answer), so you could extract it out of it and simplify the condition a bit:
select *
from ##ScheduleDetail SD
left join ##HolidayFilterTbl HF on SD.Scheduledate = HF.Testdate
where ScheduleDate = testdate and
makeup = 0 and
((HF.IsHoliday = 1 and overtime = 1) or
overtime = 0) and
DOW = 5
order by ActivityStartTime
If you are still wanting to know how to utilize a CASE Statement Expression in a WHERE Clause the CASE Expression must be compared to a value as that is the syntax understood for conditions contained within a WHERE Clause. See below a mock example.
SELECT *
FROM ##ScheduleDetail SD
LEFT JOIN ##HolidayFilterTbl HF ON SD.Scheduledate = HF.Testdate
WHERE(ScheduleDate = testdate)
AND
/* If you wish to stick with using a CASE Expression within the WHERE Clause set the the CASE Expression equal to 'something'. I usually stick with 1 or 0 'true/false'.
| You simply have to create your own True/False evaluation. You can add your logic checks within a CASE Expression within
| the WHERE Clause and when your logic is TRUE THEN return 1. Basically you are saying when 1 = 1 then return Record.
*/
1 =
Case
WHEN HF.IsHoliday = 1 AND makeup = 0 THEN
CASE WHEN (overtime = 1 OR overtime = 0) THEN 1 END /* Return 1 here to evaluation to TRUE */
ELSE
0 /* You can add another CASE here if needed and when the condition you write in evaluations to 1 'true' return record */
END
AND
DOW = 5
ORDER BY ActivityStartTime;
There are a few reasons I've used CASE Expressions within a WHERE Clause over using AND/ORs. Just one minor reason is it allows me to contain and organize logic in a WHERE Clause inside CASE Expressions rather than having multiple AND/ORs all nested together. I've also found that using CASE Expressions in the WHERE Clause is useful when encountering Dynamic queries that accept variables to be later inserted into the SQL before being sent to the database for processing. In the case of using Dynamic SQL there are times when a CASE Statement MUST be used due to the fact that there could be data that is being compared against in the WHERE clause that is NOT a column.field value but a hardcoded value that is compared to perhaps a user selection or status (as examples)... it might be a static value passed in via the application which is how my web application works that I support which is why I bring it up.
Basically it's good to know how to use a CASE Expression in a WHERE Clause as there are some cases when the ONLY way to evaluate certain data is by using a CASE Expression .
I have no data to test this against and that's not the point. The point of my answer is to simply provide to you an alternative to the existing answer. In my opinion this logic is basic and the already provided answer is the correct one however my answer is to demonstrate how you could go about using a CASE in a WHERE Clause.
If interested see this SO Post for the differences between a CASE Statement vs a CASE Expression however know that this terminology slightly differs between databases.
As an example of this... SQL Server refers to these as Simple vs Searched but refers to all of it as a CASE Expression. Therefore a CASE Expression can either be a Simple or a Searched CASE that can be used within a Statement.

SQL Group by CASE result

I have a simple SQL query on IBM DB2. I'm trying to run something as below:
select case when a.custID = 42285 then 'Credit' when a.unitID <> '' then 'Sales' when a.unitID = '' then 'Refund'
else a.unitID end TYPE, sum(a.value) as Total from transactions a
group by a.custID, a.unitID
This query runs, however I have a problem with group by a.custID - I'd prefer not to have this, but the query won't run unless it's present. I'd want to run the group by function based on the result of the CASE function, not the condition pool behind it. So, I'm looking something like:
group by TYPE
However adding group by TYPE reports an error message "Column or global variable TYPE not found". Also removing a.custID from group section reports "Column custID or expression in SELECT list not valid"
Is this going to be possible at all or do I need to review my CASE function and avoid using the custID column since at the moment I'm getting a grouping also based on custID column, even though it's not present in SELECT.
I understand why the grouping works as it does, I'm just wondering if it's possible to get rid of the custID grouping, but still maintain it within CASE function.
If you want terseness of code, you could use a subquery here:
SELECT TYPE, SUM(value) AS Total
FROM
(
SELECT CASE WHEN a.custID = 42285 THEN 'Credit'
WHEN a.unitID <> '' THEN 'Sales'
WHEN a.unitID = '' THEN 'Refund'
ELSE a.unitID END TYPE,
value
FROM transactions a
) t
GROUP BY TYPE;
The alternative to this would be to just repeat the CASE expression in the GROUP BY clause, which is ugly, but should still work. Note that some databases (e.g. MySQL) have overloaded GROUP BY and do allow aliases to be used in at least some cases.

AND OR SQL operator with multiple records

I have the following query where if brand1/camp1 taken individually, query returns the correct value but if I specify more than one brand or campaigns, it returns some other number and I am not sure what the math is behind that. It is not the total of the two either.
I think it is IN operator that is specifying OR with "," as opposed to what I require it to do which is consider AND
select campaign,
sum(case when campaign in ('camp1', 'camp2') and description in ('brand1', 'brand2') then orders else 0 end) as brand_convs
from data.camp_results
where campaign in ('camp1', 'camp2') and channel='prog' and type='sbc'
group by campaign
having brand_convs > 0
order by brand_convs desc;
Any thoughts?
The problem is in the IN part as you suspected: The two IN operators do not affect eachother in any way, so campaign can be camp1 while description is brand2.
If your DBMS supports multiple columns in an IN statement, you use a single IN statement:
SELECT campaign, SUM(
CASE WHEN (campaign, description) IN (
('camp1', 'brand1'),
('camp2', 'brand2')
) THEN orders ELSE 0 END
) [rest of query...]
If not, you're probably going to have to use ANDs and ORs
SELECT campaign, SUM(
CASE WHEN
(campaign='camp1' AND description='brand1')
OR (campaign='camp2' AND description='brand2')
THEN orders ELSE 0 END
) [rest of query...]

Update column within CASE statement with results of a subquery postgres

I need to update a column based on the results of a subquery. If the subquery returns results for that column then the columns must be updated, is the query returns no results for that column then I need to update with 0.
I do not know where to place the subquery and how to combine it with the CASE statement. This is what I thought but the syntax is not correct. Can anybody help please?
(SELECT datazones.ogc_fid, count(*) as total
FROM suppliersnew suppliers, datazone_report_resupply datazones
WHERE St_contains(datazones.geom, suppliers.geometry) AND (suppliers.status = 'Under construction' OR
suppliers.status = 'Unknown' OR suppliers.status = 'Operational') GROUP by datazones.ogc_fid ORDER BY total ASC) sources
UPDATE datazone_report_resupply
SET es_actual =
CASE
WHEN datazone_report_resupply.ogc_fid = sources.ogc_fid THEN sources.total
ELSE 0
END
The query is a little hard to follow, because the aggregation is on the outer column (this is unusual). However, you don't need aggregation or order by. You only seem to care whether a row exists.
I think the logic is:
UPDATE datazone_report_resupply r
SET es_actual =
(CASE WHEN EXISTS (SELECT 1
FROM suppliersnew s
WHERE St_contains(r.geom, s.geometry) AND
s.status IN ('Under construction', 'Unknown', 'Operational')
)
THEN 1 ELSE 0
END);

SQL Server Update via Select Statement

I have the following sql statement and I want to update a field on the rows returned from the select statement. Is this possible with my select? The things I have tried are not giving me the desired results:
SELECT
Flows_Flows.FlowID,
Flows_Flows.Active,
Flows_Flows.BeatID,
Flows_Flows.FlowTitle,
Flows_Flows.FlowFileName,
Flows_Flows.FlowFilePath,
Flows_Users.UserName,
Flows_Users.DisplayName,
Flows_Users.ImageName,
Flows_Flows.Created,
SUM(CASE WHEN [Like] = 1 THEN 1 ELSE 0 END) AS Likes,
SUM(CASE WHEN [Dislike] = 1 THEN 1 ELSE 0 END) AS Dislikes
FROM Flows_Flows
INNER JOIN Flows_Users ON Flows_Users.UserID = Flows_Flows.UserID
LEFT JOIN Flows_Flows_Likes_Dislikes ON
Flows_Flows.FlowID=Flows_Flows_Likes_Dislikes.FlowID
WHERE Flows_Flows.Active = '1' AND Flows_Flows.Created < DATEADD(day, -60, GETDATE())
Group By Flows_Flows.FlowID, Flows_Flows.Active, Flows_Flows.BeatID,
Flows_Flows.FlowTitle, Flows_Flows.FlowFileName, Flows_Flows.FlowFilePath,
Flows_Users.UserName, Flows_Users.DisplayName, Flows_Users.ImageName,
Flows_Flows.Created
Having SUM(CASE WHEN [Like] = 1 THEN 1 ELSE 0 END) = '0' AND SUM(CASE WHEN [Dislike] = 1
THEN 1 ELSE 0 END) >= '0'
This select statement returns exactly what I need but I want to change the Active field from 1 to 0.
yes - the general structure might be like this: (note you don't declare your primary key)
UPDATE mytable
set myCol = 1
where myPrimaryKey in (
select myPrimaryKey from mytable where interesting bits happen here )
Because you haven't made your question more clear in what result you want to achieve, I'll provide an answer with my own assumptions.
Assumption
You have a select statement that gives you stuffs, and it works as desired. What you want it to do is to make it return results and update those selected rows on the fly - basically like saying "find X, tell me about X and make it Y".
Anwser
If my assumption is correct, unfortunately I don't think there is any way you can do that. A select does not alter the table, it can only fetch information. Similarly, an update does not provide more detail than the number of rows updated.
But don't give up yet, depending on the result you want to achieve, you have alternatives.
Alternatives
If you just want to update the rows that you have selected, you can
simply write an UPDATE statement to do that, and #Randy has provided
a good example of how it will be written.
If you want to reduce calls to server, meaning you want to make just
one call to the server and get result, as well as to update the
rows, you can write store procedures to do that.
Store procedures are like functions you wrote in programming languages. It essentially defines a set of sql operations and gives them a name. Each time you call that store procedure, the set of operations gets executed with supplied inputs, if any.
So if you want to learn more about store procedures you can take a look at:
http://www.mysqltutorial.org/introduction-to-sql-stored-procedures.aspx
If I understand correctly you are looking for a syntax to be able to select the value of Active to be 0 if it is 1. The syntax for something like that is
SELECT
Active= CASE WHEN Active=1 THEN 0 ELSE Active END
FROM
<Tables>
WHERE
<JOIN Conditions>