I'm having some trouble grasping the use of CASE statements (used to using If/Then). I would like to convert this to CASE format:
If DATEPART(Month,Datetime) = 04
Then UPDATE DB1
SET column1 = (SELECT Value FROM DB2)
So if the month of the current datetime matches 4 (April), then update column1 of DB1 with the values in the Value column of DB2. How would this look using CASE?
I am unclear what case has to do with this. The case statement would normally be used in a select to execute conditional statements. Your update seems more like:
update db1
set column1 = db2.value
from db1 join
db2
on db1.foo = db2.bar
where DATEPART(Month, db1.Datetime) = 4;
But it is a bit hard to divine from your question what you are really trying to do.
EDIT: (in response to comment)
For todays date, the where clause should be:
where datepart(month, getdate()) = 4
Instead of the where, you can use if (datepart(month, getdate()) = 4) . . ..
The join (or subquery) is needed because the question refers to two tables.
IF ((SELECT DATEPART(MONTH, GetDate())) = 04)
UPDATE
db1
SET
column1 = db2.value
FROM
db2
WHERE
db1.key = db2.key
The DATEPART() is embedded in a SELECT which is itself enclosed in ().
The WHERE clause is needed to specify which rows in db2 are used to update which rows in db1.
In T-SQL there is no THEN. See here for details.
I don't think there is equal CASE statement for your query.
Check CASE express in MSDN
Evaluates a list of conditions and returns one of multiple possible result expressions.
Your query is a conditional UPDATE operation which doesn't return anything. Could you clarify your intention here?
Related
I'm looking to update SQL Server in a single query based on a date, however the value updated depends on whether it is greater or lower than a provided value (in this scenario a date).
UPDATE table
SET id = 'over'
WHERE date > '2022-01-01'
UPDATE table
SET id = 'under'
WHERE date < '2022-01-01'
I can do this individually via the queries above. My question is, is there a way in SQL Server to combine these two queries and run this update in a single update query?
EDIT: to show the SET values are strings.
Try something like this
UPDATE table
SET id = case
when (date > '2022-01-01') then over
when (date < '2022-01-01') then under
end;
You may use CASE expression to evaluate all possible conditions and return the appropriate values for each condition. Note, that if you omit the ELSE part of the CASE and no condition evaluates to TRUE, the result is NULL.
UPDATE [table]
SET [id] = CASE
WHEN [date] > '20220101' THEN 'over'
WHEN [date] < '20220101' THEN 'under'
ELSE ''
END
I have a table that I want to update that contains a column called 'expiration_days'. What I am doing is trying to update the records in the 'expiration_days' column by using an 'alias column' (not sure what to call it) that is apart of a subquery where I calculated the number of days until a user's password has expired. The column from the subquery that I want to take the values from and update them in the actual table is called 'countdown'. I named the subquery results 'query' (derived table). So far I have this:
UPDATE LOGIN_INFO
SET expiration_days = query.countdown
FROM (
select li.name as name, countdown = 365 - datediff(day, sl.pwdate, getdate())
from master..syslogins sl, LOGIN_INFO li
where li.name = sl.name) query
WHERE LOGIN_INFO.name = query.name
The issue I am having is I get this error: You cannot use a derived table in the FROM clause of an UPDATE or DELETE statement. ( I also get: Incorrect syntax near ')' on the subquery where clause)
Is there a way I can take the results from the calculated column in a select statement and update the column in the LOGIN_INFO table in one query or some other easy clean way?
Perhaps something along the lines of:
update login_info
set expiration_days = (select 365 - datediff(day,s1.pwdate,getdate())
from master..syslogins s1
where s1.name = li.name)
from login_info li
where exists(select 1
from master..syslogins s2
where s2.name = li.name)
NOTES:
the exists() clause is added to insure we don't erroneously update a row in login_info that doesn't have a match in syslogins, otherwise OP will need to modify the logic accordingly (ie, what to set expiration_days to if a matching rows does not exist in syslogins?)
if syslogins.pwdate is NULLable (I don't have access to a running ASE instance at the moment) then OP will need additional logic to handle the scenario where s1.pwdate is NULL; default countdown to some hardcoded value? or perhaps modify the exists() to include the additional clause and s2.pwdate is not NULL?
I would like to know if is it possible to use the clause "with as" with a variable and/or in a block begin/end.
My code is
WITH EDGE_TMP
AS
(select edge.node_beg_id,edge.node_end_id,prg_massif.longueur,prg_massif.lgvideoupartage,prg_massif.lgsanscable from prg_massif
INNER JOIN edge on prg_massif.asset_id=edge.asset_id
where prg_massif.lgvideoupartage LIKE '1' OR prg_massif.lgsanscable LIKE '1')
,
journey (TO_TOWN, STEPS,DISTANCE,WAY)
AS
(SELECT DISTINCT node_beg_id, 0, 0, CAST(&&node_begin AS VARCHAR2(2000))
FROM EDGE_TMP
WHERE node_beg_id = &&node_begin
UNION ALL
SELECT node_end_id, journey.STEPS + 1
, journey.DISTANCE + EDGE_TMP.longueur,
CONCAT(CONCAT(journey.WAY,';'), EDGE_TMP.node_end_id
)
It create a string as output separated by a ; but i need to get it back as variable or table do you know how? I used a concat to retrieve data in a big string. Can i use a table to insert data
,
A need to use the result to proceed more treatment.
Thank you,
mat
No, WITH is a part of an SQL statement only. But if you describe why you need it in pl/sql, we'll can advice you something.
Edit: if you have SQL statement which produces result you need, you can assign it's value to pl/sql variable. There are several methods to do this, simpliest is to use SELECT INTO statement (add INTO variable clause into your select).
You can use WITH clause as a part of SELECT INTO statement (at least in not-too-very-old Oracle versions).
I have below query that I am using ..
select * from app_subsys_param where assp_name like '%param_name%'
where param_name is the name of the parameter. From this query we will get the assp_id corresponding to the parameter. With this id we look up into app_subsys_parmval table to get the value of the parameter.
update app_subsys_parmval set aspv_value = 'true' where assp_id = id_val
Now instead of separately launching the two sql statements , I want to combime both of them as one is there any sub query or join mechanism that can combine both of them in one statement , please advise
You need to use UPDATE .. FROM syntax:
UPDATE app_subsys_paramval
SET aspv_value = 'true'
FROM app_subsys_param
WHERE app_subsys_param.id = app_subsys_paramval.id
AND app_subsys_param.value LIKE '%param_name%';
Use a subselect in your update statement:
UPDATE app_subsys_parmval
SET aspv_value = 'true'
WHERE id_val = (SELECT assp_id
FROM app_subsys_param
WHERE assp_name LIKE '%param_name%')
Note, I am assuming a bit about what's in the * of your select *.
Look at the MERGE statement. This is the ANSI SQL:2003 standard for UPDATE … FROM.
Documentation:
MERGE for DB2 for Linux/UNIX/Windows
MERGE for DB2 z/OS 9.1
Can anyone please point out what is wrong with the following SQL statement:
SELECT DiaryType
FROM tblDiaryTypes
WHERE DiaryType NOT IN (SELECT NextDiary
FROM tblActionLinks
WHERE HistoryType = 'Info Chased');
Now the nested SELECT statement currently returns NULL because there are initially no entries in tblActionLinks, and I am wondering if that is the issue.
The outer SELECT statement if executed on its own does return all the Diary Types from tblDiaryTypes as expected. But when I add the nested SELECT statement to exclusde certain values, then the overall SQL statement returns empty!
Does this have something to do withthe fact that tblActionLinks is currently empty? If so, how can I amend my SQL statement to handle that possibility.
For SQL SERVER (you didn't specified sql engine) try with:
SELECT ISNULL(NextDiary, 0) ...
When no rows found all value is null then it will return 0
Are you sure there are no entries currently in tblActionLinks? If there are no entries in tblActionLinks, then outer query should return all records
Does this have something to do withthe fact that tblActionLinks is currently empty?
Yes... NULL doesn't being handled so good in SQL, Comparing a value to NULL is undifned try give for null a flag value like -999:
SELECT DiaryType
FROM tblDiaryTypes
WHERE DiaryType NOT IN (SELECT NVL(NextDiary, -999) -- <===
FROM tblActionLinks
WHERE HistoryType = 'Info Chased');
NVL(NextDiary, -999) means that if NextDiary IS NULL, replace the value with -999
docs
I would rewrite your query the following way:
SELECT DiaryType
FROM tblDiaryTypes
WHERE NOT EXISTS (SELECT NextDiary
FROM tblActionLinks
WHERE HistoryType = 'Info Chased'
AND NextDiary = DiaryType)
This ensures proper behaviour irrespective of ANSI_NULLS setting and you don't have to worry about properly choosing the magic value returned by ISNULL(NextDiary, 0) (what if you have DiaryType equal to 0 in tblDiaryTypes?)