Use generated column to create another column - SQL Server - sql

I have a column that gets generated using CAST(CASE WHEN A and B THEN SSS) as Name
Now I need another column which will use the value of the column above in the same way (CASE WHEN Name SSS THEN 123)
Is that possible?
UPDATE:
Example:
I have a table with
Name, Age, UserCode, UserId
I would like to generate a table using SELECT which includes
Name, UserCode, UserName
Name: returned from the column Name
UserCode:
CAST(CASE WHEN UserCode = 'A' and UserId = 'B' THEN 'SSS'
CASE WHEN UserCode = 'C' and UserId = 'Z' THEN 'ZAZ')
UserName: use the result from UserCode, so if UserCode is SSS then UserName become SAR123 etc...

Try this:
Select *,
CASE UserCode
When 'SSS' Then 'SAR123'
--When ... --<<Put other When clauses here
END AS UserName
FROM(
Select Name ,
CASE WHEN UserCode = 'A' and UserId = 'B' THEN 'SSS'
WHEN UserCode = 'C' and UserId = 'Z' THEN 'ZAZ'
END AS UserCode
From Table
) AS K

The alias of column name are obtained after the FROM, WHERE and then SELECT clause code evaluation .. so these alias are not available before this evalution is finished for this reason
alias of column name are not allowed in select or where clause and for these clause you must rewrite the code when need
select (CASE WHEN CAST(CASE WHEN A and B THEN SSS .....) SSS THEN 123 .... )
FROM my_table
.......
but alias for column name are available for ORDER BY and GROUP BY (clause that are evalueted after the previous mentioned)
alias of coulmn can be used in order by and group by

Related

Find records only all value are same in column otherwise return 0

I have the following table
id
name
1
Gaurav
1
Ram
1
Gaurav
1
Gaurav
From the above table I want to fetch records if name have same value as Gaurav. For example one row has name Ram so it should not return any thing. If all value is Gaurav then return id.
On MySQL, you could use aggregation:
SELECT id
FROM yourTable
GROUP BY id
HAVING SUM(name = 'Gaurav') = COUNT(*);
On all databases:
SELECT id
FROM yourTable
GROUP BY id
HAVING COUNT(CASE WHEN name = 'Gaurav' THEN 1 END) = COUNT(*);
You can try this as well. Bit hardcoded. You can use 0 instead of null and remove where clause as well if you want.
SELECT Case When Name ='Gaurav' Then ID else NULL END AS ID
FROM Yourtable
where name ='Gaurav'

BigQuery(standard SQL) grouping values based on first CASE WHEN statement

Here is my query with the output below the syntax.
SELECT DISTINCT CASE WHEN id = 'RUS0261431' THEN value END AS sr_type,
COUNT(CASE WHEN id in ('RUS0290788') AND value in ('1','2','3','4') THEN respondentid END) AS sub_ces,
COUNT(CASE WHEN id IN ('RUS0290788') AND value in ('5','6','7') THEN respondentid END) AS pos_ces,
COUNT(*) as total_ces
FROM `some_table`
WHERE id in ( 'RUS0261431') AND id <> '' AND value IS NOT NULL
GROUP BY 1
As you can see with the attached table I'm unable to group the values based on Id RUS0290788 with the distinct values that map to RUS0261431. Is there anyway to pivot with altering my case when statements so I can group sub_ces and pos_ces by sr_type. Thanks in advanceenter image description here
You can simplify your WHERE condition to WHERE id = ('RUS0261431'). Only records with this value will be selected so you do not have to repeat this in the CASE statements.

Select an ID if count is equal to 1

I am trying to write a query which needs to find an ID number from 3 WHERE values based on the result only being equal to 1.
So say i want to find a patient's ID and my where clause matches the firstname, lastname and DOB. If there are 2 results because of duplicates, i need the output to be NIL else it should return the patient ID.
if(select count(*)
from patient
where last_name = 'JAMES'
and first_name = 'JONES'
and birth_DtTM = '1980-01-01') > 1
print 'NULL' else return Pat_ID1
This is kind of what i am leading towards.
Thanks guys
select case when count(*)> 1
then 'NULL' else Pat_ID1 end
from patient
where last_name = 'JAMES'
and first_name = 'JONES'
and birth_DtTM = '1980-01-01'
group by Pat_ID1
try below.
;WITH CTE(Pat_ID1,last_name,first_name,birth_DtTM,dup_rows)
as
(
SELECT Pat_ID1,last_name,first_name,birth_DtTM,ROW_NUMBER() OVER(PARTITION BY last_name,first_name,birth_DtTM ORDER BY Pat_ID1) AS dup_rows FROM patient
)
SELECT
case when dup_rows>1 then null
when dup_rows=1 then Pat_ID1
end
FROM CTE
You can do it like this:
SELECT
PatientID = CASE COUNT(*) WHEN 1 THEN MAX(Pat_ID1) END
FROM
patient
WHERE
last_name = 'JAMES'
AND first_name = 'JONES'
AND birth_DtTM = '1980-01-01'
;
The CASE expression will evaluate either to the single Pat_ID1 matching the request or to NULL (if COUNT(*) is anything but 1).
As you can see, the Pat_ID1 value is obtained with the help of an aggregate function (by the way, you can use MIN instead of MAX just as well). This is because the presence of COUNT(*) in the query automatically implies grouping and now, if you want to reference columns of the underlying row set, you must only access their aggregated values.

SQL CASE SUBQUERY COUNT

I have table with 2 col :
UID NAME
-----------
111 AAA
222 BBB
Customer will enter the name and I have to retrieve UID with respective value. If name won't present in the rows, it has to retrieve 000, not like no rows.
I am trying to write query like this:
SELECT
CASE UID
WHEN Count(*) = 0 THEN '000'
ELSE UID
END
FROM table1
WHERE NAME ='XXX'
Please help me in this regard. Thanks in advance...
If UID is an integer, then you need to take casts into account:
select coalesce(cast(max(uid) as char(3)), '000')
from table1
where name = 'XXX'
The cast is intended to be to the type of UID, which seems to be char(3) in your example.
When there are no matching rows, then the max() function returns NULL. The coalesce() turns this into the value you are looking for.
try this
select case
when max(id) is null then
0
else
max(id)
end
from table1
where name = 'b'
You have error in case
SELECT case when count(UID) = 0 THEN '000' ELSE UID end FROM table1 where name = 'XXX'
sqlfiddle :http://www.sqlfiddle.com/#!2/257ea/1

sql query with a case when returning more than one row

I'm trying to do a query with a case when condition to see what list I will show but I'm having this error ORA-01427: single-row subquery returns more than one row.
the query is this:
SELECT
CASE WHEN action_type like 'Trigger Severity' THEN (select cast(SEVERITY as varchar2(255)) name from SURV_TRIGGER_SEVERITY_LIST)
WHEN action_type like 'Host Group' then (select cast(name as varchar2(255)) name from Surv_List.groups)
WHEN action_type like 'Host' then (select cast(name as varchar2(255)) name from tn_tree)
END display_value
FROM surv_action_type_list
WHERE id = 0
is it possible to call a query with more than one row inside a case condition?
I would do this in multiple steps. Get the action type, then issue the appropriate query. Whether you have this logic at the front end or in a stored procedure is up you and probably depends on a lot of other things.
If you absolutely needed to do it this way, then you could try something like this:
SELECT
SQ.display_value
FROM
surv_action_type_list SATL
INNER JOIN
(
SELECT
'Trigger Severity' action_type,
CAST(severity AS VARCHAR2(255)) display_value
FROM
SURV_TRIGGER_SEVERITY_LIST
UNION ALL
SELECT
'Host Group' action_type,
CAST(name AS VARCHAR2(255) display_value
FROM
Surv_List.groups
UNION ALL
SELECT
'Host' action_type,
CAST(name AS VARCHAR2(255) display_value
FROM
tn_tree
) SQ ON
SQ.action_type = SATL.action_type
WHERE
SATL.id = 0
You have 3 sub-queries.
1. select cast(SEVERITY as varchar2(255)) name from SURV_TRIGGER_SEVERITY_LIST
2. select cast(name as varchar2(255)) name from Surv_List.groups
3. select cast(name as varchar2(255)) name from tn_tree
Each one must return 0 or 1 rows but not more.
No. Your subquery should return only one value (only one row and one column) since you'll display it on a single row.
Since you are displaying the value as one column using your query above, it looks like your intention is to get only one value.
select
CASE WHEN action_type like 'Trigger Severity' THEN (select cast(SEVERITY as varchar2(255)) name from SURV_TRIGGER_SEVERITY_LIST)
WHEN action_type like 'Host Group' then (select cast(name as varchar2(255)) name from Surv_List.groups)
WHEN action_type like 'Host' then (select cast(name as varchar2(255)) name from tn_tree)
END display_value
from surv_action_type_list
where id = 0
Is there a where missing that links this ID to say a Severity list?
Usually queries like this would have a condition in the subquery.. something like..
select
CASE WHEN action_type like 'Trigger Severity'
THEN (select cast(SEVERITY as varchar2(255)) name
**from SURV_TRIGGER_SEVERITY_LIST trglst
where trglst.name = lst.severity_name**
-----
---
END display_value
from surv_action_type_list lst
where id = 0