I have developed a query, and in the results for the first three columns I get NULL. How can I replace it with 0?
Select c.rundate,
sum(case when c.runstatus = 'Succeeded' then 1 end) as Succeeded,
sum(case when c.runstatus = 'Failed' then 1 end) as Failed,
sum(case when c.runstatus = 'Cancelled' then 1 end) as Cancelled,
count(*) as Totalrun from
( Select a.name,case when b.run_status=0 Then 'Failed' when b.run_status=1 Then 'Succeeded'
when b.run_status=2 Then 'Retry' Else 'Cancelled' End as Runstatus,
---cast(run_date as datetime)
cast(substring(convert(varchar(8),run_date),1,4)+'/'+substring(convert(varchar(8),run_date),5,2)+'/' +substring(convert(varchar(8),run_date),7,2) as Datetime) as RunDate
from msdb.dbo.sysjobs as a(nolock) inner join msdb.dbo.sysjobhistory as b(nolock)
on a.job_id=b.job_id
where a.name='AI'
and b.step_id=0) as c
group by
c.rundate
When you want to replace a possibly null column with something else, use IsNull.
SELECT ISNULL(myColumn, 0 ) FROM myTable
This will put a 0 in myColumn if it is null in the first place.
You can use both of these methods but there are differences:
SELECT ISNULL(col1, 0 ) FROM table1
SELECT COALESCE(col1, 0 ) FROM table1
Comparing COALESCE() and ISNULL():
The ISNULL function and the COALESCE expression have a similar
purpose but can behave differently.
Because ISNULL is a function, it is evaluated only once. As
described above, the input values for the COALESCE expression can be
evaluated multiple times.
Data type determination of the resulting expression is different.
ISNULL uses the data type of the first parameter, COALESCE follows
the CASE expression rules and returns the data type of value with
the highest precedence.
The NULLability of the result expression is different for ISNULL and
COALESCE. The ISNULL return value is always considered NOT NULLable
(assuming the return value is a non-nullable one) whereas COALESCE
with non-null parameters is considered to be NULL. So the
expressions ISNULL(NULL, 1) and COALESCE(NULL, 1) although
equivalent have different nullability values. This makes a
difference if you are using these expressions in computed columns,
creating key constraints or making the return value of a scalar UDF
deterministic so that it can be indexed as shown in the following
example.
-- This statement fails because the PRIMARY KEY cannot accept NULL values
-- and the nullability of the COALESCE expression for col2
-- evaluates to NULL.
CREATE TABLE #Demo
(
col1 integer NULL,
col2 AS COALESCE(col1, 0) PRIMARY KEY,
col3 AS ISNULL(col1, 0)
);
-- This statement succeeds because the nullability of the
-- ISNULL function evaluates AS NOT NULL.
CREATE TABLE #Demo
(
col1 integer NULL,
col2 AS COALESCE(col1, 0),
col3 AS ISNULL(col1, 0) PRIMARY KEY
);
Validations for ISNULL and COALESCE are also different. For example,
a NULL value for ISNULL is converted to int whereas for COALESCE,
you must provide a data type.
ISNULL takes only 2 parameters whereas COALESCE takes a variable
number of parameters.
if you need to know more here is the full document from msdn.
With coalesce:
coalesce(column_name,0)
Although, where summing when condition then 1, you could just as easily change sum to count - eg:
count(case when c.runstatus = 'Succeeded' then 1 end) as Succeeded,
(Count(null) returns 0, while sum(null) returns null.)
When you say the first three columns, do you mean your SUM columns? If so, add ELSE 0 to your CASE statements. The SUM of a NULL value is NULL.
sum(case when c.runstatus = 'Succeeded' then 1 else 0 end) as Succeeded,
sum(case when c.runstatus = 'Failed' then 1 else 0 end) as Failed,
sum(case when c.runstatus = 'Cancelled' then 1 else 0 end) as Cancelled,
SQL Fiddle Demo
A Simple way is
UPDATE tbl_name SET fild_name = value WHERE fild_name IS NULL
If you are using Presto, AWS Athena etc, there is no ISNULL() function. Instead, use:
SELECT COALESCE(myColumn, 0 ) FROM myTable
Wrap your column in this code.
ISNULL(Yourcolumn, 0)
Maybe check why you are getting nulls
Use COALESCE, which returns the first not-null value e.g.
SELECT COALESCE(sum(case when c.runstatus = 'Succeeded' then 1 end), 0) as Succeeded
Will set Succeeded as 0 if it is returned as NULL.
Add an else to your case statements so that they default to zero if the test condition is not found. At the moment if the test condition isn't found NULL is being passed to the SUM() function.
Select c.rundate,
sum(case when c.runstatus = 'Succeeded' then 1 else 0 end) as Succeeded,
sum(case when c.runstatus = 'Failed' then 1 else 0 end) as Failed,
sum(case when c.runstatus = 'Cancelled' then 1 else 0 end) as Cancelled,
count(*) as Totalrun from
( Select a.name,case when b.run_status=0 Then 'Failed' when b.run_status=1 Then 'Succeeded'
when b.run_status=2 Then 'Retry' Else 'Cancelled' End as Runstatus,
---cast(run_date as datetime)
cast(substring(convert(varchar(8),run_date),1,4)+'/'+substring(convert(varchar(8),run_date),5,2)+'/' +substring(convert(varchar(8),run_date),7,2) as Datetime) as RunDate
from msdb.dbo.sysjobs as a(nolock) inner join msdb.dbo.sysjobhistory as b(nolock)
on a.job_id=b.job_id
where a.name='AI'
and b.step_id=0) as c
group by
c.rundate
sum(case when c.runstatus = 'Succeeded' then 1 else 0 end) as Succeeded,
sum(case when c.runstatus = 'Failed' then 1 else 0 end) as Failed,
sum(case when c.runstatus = 'Cancelled' then 1 else 0 end) as Cancelled,
the issue here is that without the else statement, you are bound to receive a Null when the run status isn't the stated status in the column description. Adding anything to Null will result in Null, and that is the issue with this query.
Good Luck!
by following previous answers I was losing my column name in SQL server db however following this syntax helped me to retain the ColumnName as well
ISNULL(MyColumnName, 0) MyColumnName
For regular SQL, ISNULL(item) can only take one parameter, and thus 90% of these solutions don't work.
I repurposed #Krishna Chavali's answer to make this:
(CASE WHEN (NOT ISNULL(column_name)) THEN column_name ELSE 0 END) AS ColumnName
This will return the value in column_name if it is not null, and 0 if it is null.
UPDATE TableName SET ColumnName= ISNULL(ColumnName, 0 ) WHERE Id = 10
Related
I am querying the very popular AdventureWorks DB in SSMS.
My objective to find the number of males and females under each job title from HumanResources.Employee.
For this my original query was,
SELECT JobTitle,
COUNT(CASE WHEN Gender='M' THEN 1
ELSE 0
END) AS MALE_COUNT,
COUNT(CASE WHEN Gender='F' THEN 1
ELSE 0
END) AS FEMALE_COUNT,Gender
FROM HumanResources.Employee
GROUP BY JobTitle,Gender
ORDER BY JobTitle
GO
However, I am getting incorrect answer with the above query.So by modifying it as below ,I am getting the desired result:
SELECT JobTitle,
COUNT(CASE WHEN Gender='M' THEN 1
END) AS MALE_COUNT,
COUNT(CASE WHEN Gender='F' THEN 1
END) AS FEMALE_COUNT,Gender
FROM HumanResources.Employee
GROUP BY JobTitle,Gender
ORDER BY JobTitle
GO
As can be easily seen, I am just removing the 'ELSE 0' condition for both the CASE statements, but am I unable to figure out as to how '0' is affecting the values returned in the result.
Can someone explain to me the difference between these two? Also I would like to know how the COUNT function is taking multiple values, when normally(say SELECT COUNT(3,3)) it doesn't work.
You want SUM(), not COUNT(): the latter takes in account every non-null value (this includes 0), so your current conditional expressions counts all rows - it is equivalent to COUNT(*)
Also, I suspect that gender should probably not appear in the SELECT and GROUP BY clauses, since that's precisely what you are trying to aggregate
I think that you want:
SELECT
JobTitle,
SUM(CASE WHEN Gender='M' THEN 1 ELSE 0 END) AS MALE_COUNT,
SUM(CASE WHEN Gender='F' THEN 1 ELSE 0 END) AS FEMALE_COUNT
FROM HumanResources.Employee
GROUP BY JobTitle
ORDER BY JobTitle
Documentations say:
COUNT(ALL expression) evaluates expression for each row in a group,
and returns the number of nonnull values.
Read more here: https://learn.microsoft.com/en-us/sql/t-sql/functions/count-transact-sql?view=sql-server-ver15
So we can rewrite your query as:
SELECT
JobTitle,
COUNT(CASE WHEN Gender='M' THEN 1 ELSE NULL END) AS MALE_COUNT,
COUNT(CASE WHEN Gender='F' THEN 1 ELSE NULL END) AS FEMALE_COUNT
FROM HumanResources.Employee
GROUP BY JobTitle
ORDER BY JobTitle
About your queries:
First query:
inside Count function you have a CASE expression which will change the 'M' to 1 and 'F' to 0. Then COUNT function will do the count operations over them. because neither 1 nor 0 are NULL so Count will return total number of records, regardless of 'M' or 'F'
This procedure is same for second CASE too.
Second query:
Inside Count function you have a CASE expression which will change 'M' to 1, but you did not mentioned what to do with other values, so NULL will be returned for non-M values. After that Count function will do the count operations on these records and will return the number of M's.(Second query is equal to the query I have posted, and they both will have the same output. However because of readability I prefer my query over yours :-) )
This procedure is same for second CASE too.
Documentations for CASE expression says:
ELSE else_result_expression Is the expression returned if no
comparison operation evaluates to TRUE. If this argument is omitted
and no comparison operation evaluates to TRUE, CASE returns NULL.
else_result_expression is any valid expression. The data types of
else_result_expression and any result_expression must be the same or
must be an implicit conversion.
Read more here: https://learn.microsoft.com/en-us/sql/t-sql/language-elements/case-transact-sql?view=sql-server-ver15
SELECT Count(3,3)
This is syntactically wrong and will give you an error like this, which is pretty self explanatory:
Msg 174, Level 15, State 1, Line 1 The Count function requires 1
argument(s)
The syntax for Count function based on the aforementioned documentations is like this:
-- Aggregation Function Syntax
COUNT ( { [ [ ALL | DISTINCT ] expression ] | * } )
-- Analytic Function Syntax
COUNT ( [ ALL ] { expression | * } ) OVER ( [ <partition_by_clause> ] )
I have an access query that I have recreate in SQL.
Access:
SELECT Columns ,
IIf([Col1]="X",IIf([COL2]<>"XXXX",1,0)) AS NEWCOL1,
IIf([COL2] Not In ("HHH","GGG"),1,0) AS [NEWCOL2],
IIf(([NEWCOL1]=1) Or ([NEWCOL2]=1),1,0) AS NEWCOL3
FROM [TABLE]
WHERE ((([TABLE].COL2)<>"XXXX")) OR ((([TABLE].COL2)<>"HHH" And ([TABLE].COL2)<>"GGG"));
In SQL :
SELECT Columns ,
"NEWCOL1" =
CASE WHEN ([COL1]='X' AND COL2<> 'XXXX') THEN 1
ELSE 0
END,
"NEWCOL2" =
CASE WHEN COL2 NOT IN ('HHH','GGG') THEN 1
ELSE 0
END ,
IIf(([NEWCOL1]=1) Or ([NEWCOL2]=1),1,0) AS NEWCOL3
FROM [TABLE]
WHERE ((([TABLE].COL2)<>'XXXX')) OR ((([TABLE].COL2)<>'HHH' And ([TABLE].COL2)<>'GGG'));
IIf(([NEWCOL1]=1) Or ([NEWCOL2]=1),1,0) AS NEWCOL3
When I use the Newcol1 and newcol2 it throws an error invalid column how could use them maybe in a nested case or iif statement
If you're in SQL 2012, where IIF() is valid, then it looks like the problem is that you don't have an ELSE value for the first outer case:
IIf([Col1]='X',IIf([COL2]<>'XXXX',1,0){,NEED SOME ELSE VALUE HERE}) AS NEWCOL1,
I don't know why this would work in Access. I guess Access must be more "dummy proof" than SQL Server.
To replace your original first IIF with a CASE, you would do this:
CASE WHEN [Col1]='X' THEN
CASE WHEN [COL2]<>'XXXX' THEN 1 ELSE 0 END
END
By not supplying an ELSE for the first condition, if [Col1] does not equal 'X', the statement will return NULL without raising an error.
To handle your most recent request with a CTE, you could do as below:
WITH cte AS (
SELECT
Columns,
CASE WHEN ([COL1]='X' AND COL2<> 'XXXX') THEN 1 ELSE 0 END AS NEWCOL1,
CASE WHEN COL2 NOT IN ('HHH','GGG') THEN 1 ELSE 0 END AS NEWCOL2
FROM [TABLE]
WHERE ((([TABLE].COL2)<>'XXXX')) OR ((([TABLE].COL2)<>'HHH' And ([TABLE].COL2)<>'GGG'))
)
SELECT *, IIf(([NEWCOL1]=1) Or ([NEWCOL2]=1),1,0) AS NEWCOL3
FROM cte;
What could be wrong with this query:
SELECT
SUM(CASE
WHEN (SELECT TOP 1 ISNULL(StartDate,'01-01-1900')
FROM TestingTable
ORDER BY StartDate Asc) <> '01-01-1900' THEN 1 ELSE 0 END) AS Testingvalue.
The get the error:
Cannot perform an aggregate function on an expression containing an aggregate or a subquery.
As koppinjo stated what your current (broken) query is doing is checking if you have a NULL-value (or StartDate = '01-01-1900') in your table, return either a 1 or a 0 depending on which, and then attempting to SUM that single value.
There are 2 different logical things you want.
Either getting the amount of rows that has a StartDate or checking if any row is missing StartDate.
SELECT --Checking if there is a NULL-value in table
(
CASE WHEN
(SELECT TOP 1 ISNULL(StartDate,'01-01-1900')
FROM TestingTable
ORDER BY StartDate Asc) <> '01-01-1900' THEN 1
ELSE 0
END
) AS TestingValue
SELECT SUM(TestingValue) TestingValue --Give the count of how many non-NULLs there is
FROM
(
SELECT
CASE WHEN
ISNULL(StartDate,'01-01-1900') <> '01-01-1900' THEN 1
ELSE 0
END AS TestingValue
FROM TestingTable
) T
Here is a SQL Fiddle showing both outputs side by side.
Hard to say, but you probably want something like this:
SELECT
SUM(TestingValue)
FROM
(SELECT
CASE
WHEN ISNULL(StartDate,'01-01-1900') <> '01-01-1900'
THEN 1
ELSE 0
END AS TestingValue
FROM TestingTable) t
As your original query is written now, your subquery will return 1 value overall, so your sum would be 1 or 0 always, not to mention it is illegal. To get around that, this SQL will apply the case statement to every row in the TestingTable and insert the result into a derived table (t), then the 'outer' select will sum the results. Hope this helps!
In my table I got a column whose value is whether 0 or 1. If that column is 0 I output the value as 'no'; if 1 I should output as 'yes' for all rows. How can I do this only using SQL statement. Thanks
I understand that this question (which shows up at the top of google results for "sql server inline if") is 2 years old, but with SQL Server 2012, the answers are somewhat outdated. It also appears to be a duplicate of SQL inline if statement type question, but that question (being an even older one), doesn't have an up to date answer either.
In SQL Server 2012 you can use the IIF function:
IIF ( boolean_expression, true_value, false_value )
Example:
SELECT IIF(someColumn = 1, 'yes', 'no')
SQL Server does not have an inline if statement, but it does have an inline case that can be use to accomplish the same.
Case has two forms, one is:
select
case MyFlag
when 1 then 'YES'
when 0 then 'NO'
else 'OOPS'
end
from MyTable
where it's used just like a switch in C-like languages and the other is:
select
case
when MyFlag = 1 then 'YES'
when MyFlag = 0 then 'NO'
-- when some unrelated condition...
else 'OOPS'
end
from MyTable
where it senquentially evaluates a list of conditions and returns the first that is fulfiled.
P.S. The end part is mandatory, and I usually forget that.
It's also usual for a simple case stament to be completely inlined, like
select (case MyFlag when 1 then 'Yes' else 'No' end) as MyFlagDesc
Two possibilities:
(CASE WHEN condition1 THEN Value1 ELSE Value2 END)
or, the most complete solution:
(CASE value_to_check WHEN Value1 THEN Result1 [WHEN ... THEN ...] ELSE OtherResult END)
Something like this:
SELECT
CASE YourColumn
WHEN 0 THEN 'no'
WHEN 1 THEN 'yes'
ELSE 'nothing'
END
FROM dbo.YourTable
I mixed three IIF in one line, I have three variables and I want to know which one is greater than zero but I know the order of priority PersonHomePhoneID , PersonWorkPhoneID and PersonCellPhoneID
IIF(#PersonHomePhoneID > 0 , #PersonHomePhoneID, IIF(#PersonWorkPhoneID > 0 , #PersonWorkPhoneID, IIF(#PersonCellPhoneID > 0 , #PersonCellPhoneID, 0)))
The answer of question :
IIF(column = 1 , 'yes', IIF(column = 0, 'no', ''))
SELECT
MyColumn = 'something'
FROM table
WHERE MyColumn == 'something'
Possible to use MyColumn in WHERE clause?
EDIT:
Here's full query:
select TOP 10
PremiumYTDCurrent=Sum(CASE WHEN
AASI.Inv_Acctcur>='201101'
and AASI.Inv_Acctcur<='201102'
THEN (AASI.Inv_Premium)*R.[Percent]
ELSE 0 END),
PremiumYTDPrevious=Sum(CASE WHEN
AASI.Inv_Acctcur>='201001'
and AASI.Inv_Acctcur<='201002'
THEN (AASI.Inv_Premium)*R.[Percent]
ELSE 0 END),
R.STAFF, L.Description, L.LINE_OF_BUSINESS
from AAS_Invoice AASI,Invoice I,Revenue_Tracking R, Policy P, Line_Of_Business L
where I.Invoice_No=convert(Char,Convert(int,AASI.Inv_Entry_Num))
and I.Invoice=R.Invoice
and I.POLICY=P.POLICY
and L.LINE_OF_BUSINESS=P.LINE_OF_BUSINESS
and R.Organization IN (SELECT ST.ORGANIZATION FROM Staff ST WHERE ST.STAFF=14407)
and R.Staff=14407
and R.Activity_type='Broker'
and R.[Percent]>0
and PremiumYTDCurrent != 0
group by R.STAFF, L.Description, L.LINE_OF_BUSINESS
order by PremiumYTDCurrent DESC, PremiumYTDPrevious DESC, average_policy DESC
You can not use the column in the where clause. Use the expression instead.
and Sum(CASE WHEN
AASI.Inv_Acctcur>='201101'
and AASI.Inv_Acctcur<='201102'
THEN (AASI.Inv_Premium)*R.[Percent]
ELSE 0 END) <> 0
Edit 1
Did not notice the SUM clause.
Try add it as a HAVING clause instead after order by.
having Sum(CASE WHEN
AASI.Inv_Acctcur>='201101'
and AASI.Inv_Acctcur<='201102'
THEN (AASI.Inv_Premium)*R.[Percent]
ELSE 0 END) != 0
You could wrap the SQL up in a nested statement, a horrendously simple example being, e.g.:
SELECT MyMadeUpColumnName, col2, AnotherMadeUpColumn FROM (
SELECT SUM(sillycolumn) AS 'MyMadeUpColumnName', col2 FROM table GROUP BY col2
) AS t
WHERE t.AnotherMadeUpColumn <> 0
Any column names that you (re)define in the derived table become the actual column names for the parent select.