I am attempting to create a row called Flag that will keep a count of when Value is above 2. Later I will need to sum flag as a count.
I currently have:
CASE
WHEN Value > 2
THEN 1
ELSE 0
END AS 'Flag',
CASE
WHEN 'Flag' = 1
THEN 1
ELSE 0
END AS 'FollowedUpCorrectly'
I receive the error:
Conversion failed when converting the varchar value 'Flag' to data
type int.
How can I force the 1 or 0 to be an INT in order to do later math?
I've looked around and I can't seem to find a way that fits.
To be able to use previously created columns in the select, you'll need to use for example outer apply, with something like this:
select
*
from table1
outer apply (
select CASE WHEN Value > 2 THEN 1 ELSE 0 END AS Flag
) X
outer apply (
select CASE WHEN X.Flag = 1 THEN 1 ELSE 0 END AS FollowedUpCorrectly
) Y
Test this in SQL Fiddle
You could use CTE or a subquery to create a flag and then do your case statement as needed in the outer query like this:
;WITH q1
AS (
SELECT
col1
,col2
,col3
,CASE
WHEN Value > 2
THEN 1
ELSE 0
END AS 'Flag'
FROM your_table --change this to match your table and column name
)
SELECT q1.col1
,q1.col2
,q1.col3
,CASE
WHEN q1.Flag = 1
THEN 1
ELSE 0
END AS 'FollowedUpCorrectly'
FROM q1;
I might misunderstand what you are after.
CASE
WHEN Value > 2
THEN 1
ELSE 0
END AS 'Flag',
CASE
WHEN 'Flag' = 1
THEN 1
ELSE 0
END AS 'FollowedUpCorrectly'
If these two lines are in the same code block, 'Flag' is unknown in the second Case Statement.
Update: As Siyual has pointed out, Flag is a string literal. Try changing the name to something that is not a reserved word.
You are comparing a string ('Flag') to an int (1). Perhaps you meant to refer to the first case that you named 'Flag'. If so, try referring to it without using the single quotes. Then the analyzer will recognize it and accept it as an int, which it is. But 'Flag' is a string. Flag is an int.
Related
I have table called Numbers in that column I have values from 0 - 10 but I like to keep value of 1-10 only change record of 0 too null
Case numbers
when 0
then ''
but I found this has changed all values and not values that have 0 is there way I can say else leave value as is?
Do you want this?
update t
set number = null
where number = 0;
Or as a select:
select t.*,
(case when number <> 0 then number end)
from t;
SELECT CASE WHEN [column] = 0 THEN NULL ELSE [column] END AS [SomeName]
FROM Numbers
I've a table in my database for which I need to check if all rows have one field not null.
If there are no row or if there is at least 1 row with the field null => true
If there are rows and they are all with the field not null => False
Is there a way to do this in on simple query? Or I need to check if my table is empty first then if it's not check if I've a row with the field value empty ?
This will count how many NULL values you have in a field;
SELECT
SUM(CASE WHEN FieldName IS NULL THEN 1 ELSE 0 END) NullValues
FROM TableName
Will return 0 if there are no NULL values, and will return the number of NULLS if there are any present.
If you actually want to return a value as 'True' or 'False' then do this;
SELECT CASE
WHEN a.NullValues > 0
THEN 'True'
ELSE 'False'
END CheckField
FROM (
SELECT
SUM(CASE WHEN FieldName IS NULL
THEN 1
ELSE 0
END) NullValues
FROM TableName
) a
Use count(*) and count(field) and compare the two:
select
case when count(*) > 0 and count(*) = count(field) then 1 -- not empty and no nulls
else 0 end as isgood
from mytable;
Oracle SQL has no boolean data type , so I use 1 for true and 0 for false. You can replace this with whatever you like (e.g. 'true' instead of 1 and 'false' instead of 0).
As to turning this into a predicate (correlated to a main query), you'd use something along the lines of:
select ...
from main
where exists
(
select 1
from mytable
where mytable.colx = main.coly
having count(*) > 0 and count(*) = count(field)
);
You can do this with aggregation. However, it is difficult to understand what you are asking for. If you want to check that a field has no NULL values, you can do:
select (case when count(*) > 0 then 1 else 0 end) as HasNullValues
from t
where field is null;
Alternate way I found using max with putting null first:
select case when
max(field) keep (dense_rank first order by datfin desc nulls first) is null then 1
else 0 end as flag
from MYTABLE;
I have a field like this:
1月~3月
12月~1月
3月~12月
4月~12月
9月~8月
6月~7月
How can i sort that column following:
4月~12月
6月~7月
9月~8月
12月~1月
1月~3月
3月~12月
It start by 4 and end by 3 (4-5-6-7-8-9-10-11-12-1-2-3)(month)
This will do it, you need to separate out the numeric portion of your field, and also use a CASE statement:
SELECT *
FROM Table1
ORDER BY CASE WHEN CAST(LEFT(Col1, CHARINDEX('月',Col1)-1)AS INT) >= 4 THEN 1 END DESC
,CAST(LEFT(Col1, CHARINDEX('月',Col1)-1)AS INT)
Demo: SQL Fiddle
SQL Server syntax above, might vary depending on database.
order by case when col < 4 then 1 else 0 end, col
or if it's really a varchar
order by case when convert(int,substring(col,1,1)) < 4 then 1 else 0 end, col
I am trying to get my result as either 1 or 0 based on if the column note is empty or not
column is a varchar and i want the result from the query to give me a boolean value for that column note
SELECT id, product, note FROM myTABLE
what i tired is,
SELECT id, product, CASE WHEN ISNULL(note) THEN 0 ELSE 1 FROM myTable
but i am getting an error... i am sure there is simple fix to this i am missing so please help. thank you.
Try
SELECT id, product,CASE WHEN note IS NULL THEN 0 ELSE 1 END as SomeColumn
FROM myTable
to check for blank and null as well, use NULLIF
SELECT id, product,
CASE WHEN NULLIF(note,'') IS NULL THEN 0 ELSE 1 END as SomeColumn
FROM myTable
I basically want to do this:
SELECT HasComments = CASE (LEN(Comments) > 1) WHEN 1 THEN 1 ELSE 0 END FROM TableName
In other words, return a boolean telling me whether the length of Comments is greater than 1. This gives me a syntax error.
How can I accomplish this?
SELECT HasComments = CASE WHEN LEN(Comments) > 1 THEN 1 ELSE 0 END
FROM TableName
A better way would be to make Comments NULLable and check for that. Indexes could then be leveraged instead of the table-scan LEN() will cause.
you're missing the when and end
SELECT HasComments = CASE WHEN (LEN(Comments) > 1) WHEN 1 THEN 1 ELSE 0 END
FROM TableName
Since you have no WHERE clause, you're most likely returning a column of data:
SELECT CASE WHEN LEN(Comments) > 1 THEN 1 ELSE 0 END as 'HasComments'
FROM TableName
For newer SQL versions:
SELECT CASE WHEN LEN(Comments) > 1 THEN 1 ELSE 0 END FROM TableName