Case statement allow a where clause on the result - sql

I am doing the following in a query as such
case WHEN PreAllocationDespatch IS NULL THEN 0 ELSE PreAllocationDespatch END AS 'Allocated'
case WHEN LineQuantity IS NULL THEN 0 ELSE LineQuantity END AS 'Ordered'
case WHEN LineQuantity IS NULL THEN 0 ELSE LineQuantity - PreAllocationDespatch END AS 'Balance'
Which is fine and does what its meant to do but I need to be able to say
Where Balance != LineQuantity
to give me a list of products that have not been actioned yet. But cause it is a dynamic column I can't appear to do that. The columns in question are both ints.
PreAllocationDespatch
LineQuantity

You have to do a second simple second select with your where statement or use a having if your query allows it (we don't have the full query so we wouldn't know)

You could use a subquery, CTE, or lateral join to define the values.
However, it might be simpler to express the logic as:
where coalesce(LineQuantity, 0) <> PreAllocationDespatch

for a resulting value you could use having
having Balance != LineQuantity
or repeat the case in where
where (case WHEN LineQuantity IS NULL THEN 0 ELSE LineQuantity - PreAllocationDespatch END ) != LineQuantity

Related

Applying ISNULL inside of a CASE expression

I need to have a way to apply ISNULL in a CASE expression that will replace the NULL values with 0. The below code runs but still returns NULL values. Is there any way to accomplish this? There are two stock types - 'A' and blank, I am trying to get the sum of the quantity for each type.
I've tried using ISNULL inside the CASE
CASE WHEN MRP.stock_type = 'A'
THEN ISNULL(SUM(MRP.QUANTITY),0)
END AS 'Uncovered_Quantity',
CASE WHEN MRP.stock_type = ' '
THEN ISNULL(SUM(MRP.QUANTITY),0)
END AS 'Blank_Quantity',
I think you probably intended conditional aggregation:
SUM(CASE WHEN MRP.stock_type = 'A' THEN MRP.QUANTITY ELSE 0 END) as Uncovered_Quantity,
SUM(CASE WHEN MRP.stock_type = ' ' THEN MRP.QUANTITY ELSE 0 END) as Blank_Quantity,

How to use Case-When in another Case-When Condition in Oracle?

when execute the following SQL in Oracle
SELECT (CASE
WHEN (CASE
WHEN (1=1)
THEN (1=1)
ELSE (1=0)
END)
THEN 1
ELSE 0
END) "m1"
FROM "mock_table_1" "t0";
it will throw the following error message
ORA-00907: missing right parenthesis
So what should I do if I want to use Case-When in another Case-When Condition?
(You can omit the parentheses ) FROM DUAL is just for test
SELECT CASE WHEN CASE
WHEN 1=1 THEN 1
ELSE 0
END =1 THEN 1
ELSE 0 END "m1"
FROM DUAL;
CASE returns a value. So after END you can do your next condition

adding condition when case statement is true in postgresql

I have a query that where i need to put condition when case statement is true.I have tried like this but not geeting the correct value.
SELECT
name,count(CASE WHEN date_part('year',time_stamp) = 2016 THEN answ_count end) AS Year15
FROM
companies companies
where
(CASE when no_answer='f' then value_s IS not NULL or value_n IS not NULL end )
SELECT name,
count(CASE WHEN date_part('year',time_stamp) = 2016 THEN answ_count end) AS Year15
FROM
companies companies
where
CASE when no_answer='f' then value_s ELSE '1' end IS not NULL
OR CASE when no_answer='f' then value_n ELSE '1' end IS not NULL
CASE is an expression, you can only specify a value after the THEN part, not a condition like you did THEN value_s IS NOT NULL
You can't use case like that.
It's hard to figure out what you are trying to do, but test the result of the case, rather than putting the test inside the case, like this:
...
where CASE when no_answer='f' then value_s else value_n end
IS not NULL

How to count the rows which contains non zero values in sql

SELECT round(COUNT(dmd_1wk),2) AS NBR_ITEMS_1WK
FROM table;
Field dmd_1wk has so many zeros in it. How do I Count the non zero values?
It sounds like you just need to add a WHERE clause:
SELECT
round(COUNT(dmd_1wk),2) AS NBR_ITEMS_1WK
FROM table
WHERE dmd_1wk <> 0;
If you want the count of both non-zero and zero values, then you can use something like:
SELECT
round(COUNT(case when dmd_1wk <> 0 then dmd_1wk end),2) AS NBR_ITEMS_1WK_NonZero,
round(COUNT(case when dmd_1wk = 0 then dmd_1wk end),2) AS NBR_ITEMS_1WK_Zero
FROM table;
Method 1: Case Statement. This may be useful if you need to continue to process all rows (which a where clause would prevent).
SELECT count(case when dmd_1wk = 0 then 0 else 1 end) as NonZeroCount FROM MyTable
Method 2: Where Clause.
SELECT
count(1) as NonZeroCount
FROM
MyTable
WHERE
dmd_1wk <> 0
I'd like to offer another solution using NULLIF since COUNT won't count NULL values:
SELECT round(COUNT(NULLIF(dmd_1wk,0)),2) AS NBR_ITEMS_1WK
FROM table;
And here is the Fiddle.
Good luck.
Methinks bluefeets answer is probably what you are really looking for, as it sounds like you just want to count non-zeros; but this will get you a count of zero and non-zero items if that's not the case:
SELECT
ROUND(SUM(CASE NVL(dmd_1wk, 0) = 0 THEN 1 ELSE 0 END), 2) AS "Zeros",
ROUND(SUM(CASE NVL(dmd_1wk, 0) != 0 THEN 1 ELSE 0 END), 2) AS "NonZeros"
FROM table
Although there is no point in rounding a whole number, I've included your original ROUNDs as I'm guessing you're using it for formatting, but you might want to use:
TO_CHAR(SUM(...), '999.00')
as that's the intended function for formatting numbers.
You can filter them.
SELECT round(COUNT(dmd_1wk),2) AS NBR_ITEMS_1WK
FROM table
WHERE dmd_1wk <> 0;

SQL Query - Return Text based on numeric value

I am trying to work out a query where the query will perform a count (total) on a specific column. If the count is greater than 0, I want to display YES and display NO if the returned count is zero.
So, if I a query as this:
SELECT COUNT(ProblemID)
FROM dbo.ProblemInfo
WHERE (ProblemID IN (100,101,309,305,205,600,500)) AND (DEPID = '10866')
that will actually be a subquery, how do I get the subquery to display "YES" when the returned count is greater than 0 and NO if the count is 0?
I appreciate any insight and help.
select isnull(
SELECT MAX('YES')
FROM dbo.ProblemInfo
WHERE ProblemID IN (100,101,309,305,205,600,500)
AND DEPID = '10866'),
'NO')
This is a trick to return either YES if there's at least one matching row, or null if not.
The wrapping isnull call then turns a null into a NO
Here's an alternate way of querying that.
IF EXISTS(
SELECT *
FROM dbo.ProblemInfo
WHERE (ProblemID IN (100,101,309,305,205,600,500))
AND (DEPID = '10866')
)
BEGIN
SELECT 'Yes'
END
ELSE
BEGIN
SELECT 'No'
END
What I like about this method is that, for enormous data-sets, it should be noticeably faster.
try
SELECT CASE
WHEN (SELECT COUNT(ProblemID) FROM dbo.ProblemInfo WHERE (ProblemID IN (100,101,309,305,205,600,500)) AND (DEPID = '10866')) > 0
THEN 'YES'
ELSE 'NO' END
FROM YourTable
you can use case when.
SELECT
case
when COUNT(ProblemID) = 0 then 'NO'
else 'YES'
end
FROM dbo.ProblemInfo WHERE (ProblemID IN (100,101,309,305,205,600,500)) AND (DEPID = '10866')