SQL to Return 0 instead of NULL - sql

Trying to return 0 instead of NULL in the following select without success:
SELECT
IsNull(CASE WHEN TICKET IS NOT NULL THEN 1 ELSE 0 END,0) AS TICKET
FROM
TICKETS
WHERE
TICKET = '2'
Any suggestions? Thanks.

After reviewing the answers and your answer to them, I think what you want is: If no data returned, select 0 else select 1.. so:
SELECT case when exists(select 1 from tickets where ticket = '2')
then 1 else 0 end as IND

Use the CASE expression:
SELECT (CASE WHEN TICKET IS NOT NULL THEN 1 ELSE 0 END) AS TICKET
FROM TICKETS
WHERE TICKET = '2'
However, it makes no sense, because the value cannot be NULL given the WHERE clause. So, you can just do:
SELECT 1
FROM TICKETS
WHERE TICKET = '2';

Related

sql case statement IN with group by

I have a 2 column table with the columns : "user_name" and "characteristic". Each user_name may appear multiple times with a different characteristic.
The values in characteristic are:
Online
Instore
Account
Email
I want to write a sql statement that goes like this - but obviously this isn't working:
SELECT user_name,
case
when characteristic in ("online","instore") then 1
else 0
END as purchase_yn,
case
when characteristic in ("online","instore") and
characteristic in ("email",'account') then 1
else 0
END as purchaser_with_account
FROM my_table
GROUP BY user_name;
Essentially the first is a flag where I check for the presence of either value for that user_name.
The Second field is that they meet this criteria AND that they meet the criteria for having either 'email' or 'account'
An example the structure of your data would help better understand what you are trying to accomplish. But I think I get what you are trying to do.
You have to use an aggregate function in order to use a group by.
Something like SUM or AVG.
But you need first to build a pivot of your data and then you could use that pivot to check for your criterias:
This would create a table pivot that shows for each record what criterias are met:
SELECT
user_name,
case when characteristic = "online" then 1 else 0 end as online_yn,
case when characteristic = "instore" then 1 else 0 end as instore_yn,
case when characteristic = "account" then 1 else 0 end as account_yn,
case when characteristic = "email" then 1 else 0 end as email_yn,
FROM my_table
Now what you might wanted to do is to create an averaged version of these entries grouped by user_name and use those averages to create the fields you wanted. For that you need to use the same statement created earlier as an inline table :
Select
user_name,
case when avg(online_yn + instore_yn) >= 1 then 1 else 0 end as purchase_yn,
case when avg(online_yn + instore_yn) >= 1 and avg(email_yn + account_yn) >= 1 then 1 else 0 end as purchaser_with_account
From
(SELECT
user_name,
case when characteristic = "online" then 1 else 0 end as online_yn,
case when characteristic = "instore" then 1 else 0 end as instore_yn,
case when characteristic = "account" then 1 else 0 end as account_yn,
case when characteristic = "email" then 1 else 0 end as email_yn,
FROM my_table) avg_table
group by
user_name;
This should help.
It may not be efficient in terms of performance but you'll get what you want.
You just have to enclose the CASE expressions in COUNT aggregates:
SELECT user_name,
COUNT(case when characteristic in ("online","instore") then 1 END) as purchase_yn,
COUNT(case when characteristic in ("email",'account') then 1 END) as user_with_account
FROM my_table
GROUP BY user_name
If purchase_yn > 0 then you first flag is set. If purchase_yn > 0 and user_with_account > 0 then you second flag is set as well.
Note: You have to remove ELSE 0 from the CASE expressions because COUNT takes into account all not null values.
You haven't mentioned a specific RDBMS, but if SUM(DISTINCT ...) is available the following is quite nice:
SELECT
username,
SUM(DISTINCT
CASE
WHEN characteristic in ('online','instore') THEN 1
ELSE 0
END) AS purchase_yn,
CASE WHEN (
SUM(DISTINCT
CASE
WHEN characteristic in ('online','instore') THEN 1
WHEN characteristic in ('email','account') THEN 2
ELSE 0 END
)
) = 3 THEN 1 ELSE 0 END as purchaser_with_account
FROM
my_table
GROUP BY
username
If I correctly understand, if user have 'online' or 'instore', then for this user you want 1 as purchase_yn column, and if user also have 'email' or 'account', then 1 as purchaser_with_account column.
If this is correct, then one way is:
with your_table(user_name, characteristic) as(
select 1, 'online' union all
select 1, 'instore' union all
select 1, 'account' union all
select 1, 'email' union all
select 2, 'account' union all
select 2, 'email' union all
select 3, 'online'
)
-- below is actual query:
select your_table.user_name, coalesce(max(t1.purchase_yn), 0) as purchase_yn, coalesce(max(t2.purchaser_with_account), 0) as purchaser_with_account
from your_table
left join (SELECT user_name, 1 as purchase_yn from your_table where characteristic in('online','instore') ) t1
on your_table.user_name = t1.user_name
left join (SELECT user_name, 1 as purchaser_with_account from your_table where characteristic in('email', 'account') ) t2
on t1.user_name = t2.user_name
group by your_table.user_name

TWO TABLE AND ONE

HELP
I HAVE A QUERY WHO GIVES ME THIS, FOR EXAMPLE:
TICKET CAMPO
1 DPTO
1 AREA
2 DPTO
3 AREA
BUT I NEED TO REPRESENT THE TABLE LIKE THIS (WITH THE RESULT OF THE PREVIOUS QUERY):
TICKET DPTO AREA
1 SI SI
2 SI
3 SI
SOMEONE KNOWS HOW TO DO THAT?
IF YOU CAN HELP ME I WILL THANK YOU
Your query might look like this:
SELECT *
FROM some_table_you_did_not_name
If that is the case then you can solve the problem shown like this:
SELECT
TICKET,
CASE WHEN SUM(CASE WHEN CAMPO='DPTO' THEN 1 ELSE 0 END) > 0 THEN 'SI' ELSE '' END AS DPTO,
CASE WHEN SUM(CASE WHEN CAMPO='AREA' THEN 1 ELSE 0 END) > 0 THEN 'SI' ELSE '' END AS AREA
FROM some_table_you_did_not_name
GROUP BY TICKET
You could also do this with a join or a pivot.

How to add multiple case in sql

I want to add multiple cases in single line. In other words in below example if first item is NOT NULL and second item is equal to 1 then output should be 1 else 0. How can I do it?
MatchbyCatalog= (case when ISNULL(pc.ProductID,0) and tc.RawMatch=1) then 1 else 0 end)
Is this what you want?
CASE WHEN pc.ProductID IS NULL and tc.RawMatch=1 THEN 1 ELSE 0 END
You misunderstood ISNULL() , it's a function that replaces the value if it's NULL, it's not a condition . You were looking for IS NULL
That's all you need.
MatchbyCatalog= (case when ISNULL(pc.ProductID,0)=1 and tc.RawMatch=1 then 1 else 0 end)
when you say both I think you mean pc.ProductID and tc.RawMatch...
I have not you're entire sql query so I have to guess.
You have multiple solutions :
Nearly ss you have wrote when pc.ProductId = 1 and tc.RawMatch=1 then 1 else 0 :
MatchbyCatalog= (case when ISNULL(pc.ProductID,0)=1 and tc.RawMatch=1) then 1 else 0 end)
You could also use a trick : 1 * 1 should be 1 and 1 * 0 =0 so you could write (if tc.Rawmatch is a boolean sort of with values 0 or 1) :
MatchbyCatalog= ISNULL(pc.ProductID,0) * tc.RawMatch
case when {Condition} then {result}
When {Condition} then {result}
Else {result}

Count rows for two columns using two different clauses

I'm after a CTE which I want to return two columns, one with the total number of 1's and one with the total number of 0's. Currently I can get it to return one column with the total number of 1's using:
WITH getOnesAndZerosCTE
AS (
SELECT COUNT([message]) AS TotalNo1s
FROM dbo.post
WHERE dbo.checkletters([message]) = 1
--SELECT COUNT([message]) AS TotalNo0s
--FROM dbo.post
--WHERE dbo.checkletters([message]) = 0
)
SELECT * FROM getOnesAndZerosCTE;
How do I have a second column called TotalNo0s in the same CTE which I have commented in there to show what I mean.
Using conditional aggregation:
WITH getOnesAndZerosCTE AS(
SELECT
TotalNo1s = SUM(CASE WHEN dbo.checkletters([message]) = 1 THEN 1 ELSE 0 END),
TotalNo0s = SUM(CASE WHEN dbo.checkletters([message]) = 0 THEN 1 ELSE 0 END)
FROM post
)
SELECT * FROM getOnesAndZerosCTE;
For using COUNT() directly just be aware that it counts any NON-NULL values. You can omit the ELSE condition which implicitly returns NULL if not stated
SELECT
COUNT(CASE WHEN dbo.checkletters([message]) = 1 THEN 1 END) TotalNo1s
, COUNT(CASE WHEN dbo.checkletters([message]) = 0 THEN 1 END) TotalNo0s
FROM post
or, explicitly state NULL
SELECT
COUNT(CASE WHEN dbo.checkletters([message]) = 1 THEN 1 ELSE NULL END) TotalNo1s
, COUNT(CASE WHEN dbo.checkletters([message]) = 0 THEN 1 ELSE NULL END) TotalNo0s
FROM post
You can do it without CTE
select count(message) total,
dbo.checkletters(message) strLength
from post
group by dbo.checkletters(message)
having dbo.checkletters(message) in (1, 2) //All the messages with length 1 or 2

case statement doesn't go to else

I am wondering why the following query doesn't give 'N/A' when there are no rows for ENVIRON='Dev/Int'. It is returning null in the result of the query. I tried doing NVL(COUNT(*)) but that does't work either.
Any thoughts?
Thanks in advance.
SELECT G1.NAME,
(SELECT CASE
WHEN COUNT(*) > 0 AND ticket IS NOT NULL THEN 'Solved'
WHEN COUNT(*) > 0 AND ticket IS NULL THEN 'Done'
ELSE 'N/A'
END
FROM TABLE1
WHERE ENVIRON='Dev/Int' AND G1.NAME=NAME GROUP BY ENVIRON, ticket ) "Dev/Int"
FROM TABLE1 G1 group by G1.NAME
It doesn't give any rows because you are filtering them all out. The case is inside the query. When there are no rows to process, it returns NULL.
I think you just want conditional aggregation. The subqueries don't seem necessary:
SELECT G1.NAME,
(CASE WHEN SUM(CASE WHEN ENVIRON = 'Dev/Int' then 1 else 0 END) > 0 AND ticket IS NOT NULL
THEN 'Solved'
WHEN SUM(CASE WHEN ENVIRON = 'Dev/Int' then 1 else 0 END) > 0 AND ticket IS NULL
THEN 'Done'
ELSE 'N/A'
END) as "Dev/Int"
FROM TABLE1
group by G1.NAME;
EDIT:
Oops, the above left ticket out of the sum(). I think the logic you want has ticket in the sum() condition:
SELECT G1.NAME,
(CASE WHEN SUM(CASE WHEN ENVIRON = 'Dev/Int' AND ticket IS NOT NULL then 1 else 0 END) > 0
THEN 'Solved'
WHEN SUM(CASE WHEN ENVIRON = 'Dev/Int' AND ticket IS NULL then 1 else 0 END) > 0
THEN 'Done'
ELSE 'N/A'
END) as "Dev/Int"
FROM TABLE1
group by G1.NAME;
I'm surprised your original query worked at all and didn't get an error of the sort that subquery returned more than one row.