I'm trying to use MIN() aggregate function and fetch the minimum date from two columns and I was able to write the SQL query for this. But If one of the columns is having NULL values my query below is taking default date as '1900-01-01T00:00:00Z'. It should take the date from either Column1 or Column2 whichever has a value.
Here is the schema and the data SQLFiddle
+----+--------------+---------------+
| ID | ObservedDate | SubmittedDate |
+----+--------------+---------------+
| 1 | '2017-02-14' | '2017-02-15' |
| 1 | '2017-01-21' | '2017-01-22' |
| 2 | '2017-01-21' | |
+----+--------------+---------------+
Query
SELECT [ID],
CASE WHEN MIN(ObservedDate)<=MIN(SubmittedDate)
THEN COALESCE(MIN(ObservedDate),MIN(SubmittedDate))
ELSE COALESCE(MIN(SubmittedDate),MIN(ObservedDate)) end as RiskReferenceDate
FROM Measurements
group by ID
The reason I used COALESCE is because I want my query to consider the data from the column which has the value and ignore the column which has null value
Expected Result
+----+-------------------+
| ID | RiskReferenceDate |
+----+-------------------+
| 1 | '2017-01-21' |
| 2 | '2017-01-21' |
+----+-------------------+
Your problem is not NULL values. Your problem is empty strings. This is inserted as date 0.
The simplest solution is to fix your code to insert the correct value, as shown in this SQL Fiddle.
You can enforce this by adding a check constraint:
alter table Measurements add constraint chk_measurements_ObservedDate check (ObservedDate > '2000-01-01'); -- or whatever date
alter table Measurements add constraint chk_measurements_SubmittedDate check (SubmittedDate > '2000-01-01'); -- or whatever date
If you have existing data in the table, you can do:
update Measurements
set ObservedDate = NULLIF(ObservedDate, 0),
SubmittedDate = NULLIF(SubmittedDate, 0)
where ObservedDate = 0 or SubmittedDate = 0;
You can fix this in place with a bit more complexity in the query:
SELECT [ID],
(CASE WHEN MIN(NULLIF(ObservedDate, 0)) <= MIN(NULLIF(SubmittedDate, 0))
THEN COALESCE(MIN(NULLIF(ObservedDate, 0)), MIN(NULLIF(SubmittedDate, 0)))
ELSE COALESCE(MIN(NULLIF(SubmittedDate, 0)), MIN(NULLIF(ObservedDate, 0)))
END) as RiskReferenceDate
FROM Measurements
GROUP BY ID;
But I strongly urge you to fix the data.
I think the problem is being caused by the empty string you have inserted into one of your date columns, you should fix that really.
Anyway, this seems to work:
with a as (
select ObservedDate Dt
from Measurements
where ObservedDate <> ''
union all
select SubmittedDate
from Measurements
where SubmittedDate <> ''
)
select min(Dt)
from a
Related
I have a database with a lot of columns with pass, fail, blank indicators
I want to create a function to count each type of value and create a table from the counts. The structure I am thinking is something like
| Value | x | y | z |
|-------|------------------|-------------------|---|---|---|---|---|---|---|
| pass | count if x=pass | count if y=pass | count if z=pass | | | | | | |
| fail | count if x=fail | count if y=fail |count if z=fail | | | | | | |
| blank | count if x=blank | count if y=blank | count if z=blank | | | | | | |
| total | count(x) | count(y) | count (z) | | | | | | |
where x,y,z are columns from another table.
I don't know which could be the best approach for this
thank you all in advance
I tried this structure but it shows syntax error
CREATE FUNCTION Countif (columnx nvarchar(20),value_compare nvarchar(10))
RETURNS Count_column_x AS
BEGIN
IF columnx=value_compare
count(columnx)
END
RETURN
END
Also, I don't know how to add each count to the actual table I am trying to create
Conditional counting (or any conditional aggregation) can often be done inline by placing a CASE expression inside the aggregate function that conditionally returns the value to be aggregated or a NULL to skip.
An example would be COUNT(CASE WHEN SelectMe = 1 THEN 1 END). Here the aggregated value is 1 (which could be any non-null value for COUNT(). (For other aggregate functions, a more meaningful value would be provided.) The implicit ELSE returns a NULL which is not counted.
For you problem, I believe the first thing to do is to UNPIVOT your data, placing the column name and values side-by-side. You can then group by value and use conditional aggregation as described above to calculate your results. After a few more details to add (1) a totals row using WITH ROLLUP, (2) a CASE statement to adjust the labels for the blank and total rows, and (3) some ORDER BY tricks to get the results right and we are done.
The results may be something like:
SELECT
CASE
WHEN GROUPING(U.Value) = 1 THEN 'Total'
WHEN U.Value = '' THEN 'Blank'
ELSE U.Value
END AS Value,
COUNT(CASE WHEN U.Col = 'x' THEN 1 END) AS x,
COUNT(CASE WHEN U.Col = 'y' THEN 1 END) AS y
FROM #Data D
UNPIVOT (
Value
FOR Col IN (x, y)
) AS U
GROUP BY U.Value WITH ROLLUP
ORDER BY
GROUPING(U.Value),
CASE U.Value WHEN 'Pass' THEN 1 WHEN 'Fail' THEN 2 WHEN '' THEN 3 ELSE 4 END,
U.VALUE
Sample data:
x
y
Pass
Pass
Pass
Fail
Pass
Fail
Sample results:
Value
x
y
Pass
3
1
Fail
1
1
Blank
0
2
Total
4
4
See this db<>fiddle for a working example.
I think you don't need a generic solution like a function with value as parameter.
Perhaps, you could create a view grouping your data and after call this view filtering by your value.
Your view body would be something like that
select value, count(*) as Total
from table_name
group by value
Feel free to explain your situation better so I could help you.
You can do this by grouping by the status column.
select status, count(*) as total
from some_table
group by status
Rather than making a whole new table, consider using a view. This is a query that looks like a table.
create view status_counts as
select status, count(*) as total
from some_table
group by status
You can then select total from status_counts where status = 'pass' or the like and it will run the query.
You can also create a "materialized view". This is like a view, but the results are written to a real table. SQL Server is special in that it will keep this table up to date for you.
create materialized view status_counts with distribution(hash(status))
select status, count(*) as total
from some_table
group by status
You'd do this for performance reasons on a large table which does not update very often.
I have a column with entries like:
column:
156781
234762
780417
and would like to have the following:
column:
0000156781
0000234762
0000780417
For this I use the following query:
Select isnull(replicate('0', 10 - len(column)),'') + rtrim(column) as a from table)
However, I don't know how to replace the values in the whole column.
I already tried with:
UPDATE table
SET column= (
Select isnull(replicate('0', 10 - len(column)),'') + rtrim(column) as columnfrom table)
But I get the following error.
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.
The answer to your question is going to depend on the data type of your column. If it is a text column for example VARCHAR then you can modify the value in the table. If it is a number type such as INT it is the value and not the characters which is stored.
We can also express this by saying that "0" + "1" = "01" whilst 0 + 1 = 1.
In either case we can format the value in a query.
create table numberz(
val1 int,
val2 varchar(10));
insert into numberz values
(156781,'156781'),
(234762,'234762'),
(780417,'780417');
/* required format
0000156781
0000234762
0000780417
*/
select * from numberz;
GO
val1 | val2
-----: | :-----
156781 | 156781
234762 | 234762
780417 | 780417
UPDATE numberz
SET val1 = isnull(
replicate('0',
10 - len(val1)),'')
+ rtrim(val1),
val2 = isnull(
replicate('0',
10 - len(val2)),'')
+ rtrim(val2);
GO
3 rows affected
select * from numberz;
GO
val1 | val2
-----: | :---------
156781 | 0000156781
234762 | 0000234762
780417 | 0000780417
select isnull(
replicate('0',
10 - len(val1)),'')
+ rtrim(val1)
from numberz
GO
| (No column name) |
| :--------------- |
| 0000156781 |
| 0000234762 |
| 0000780417 |
db<>fiddle here
Usually, when we need to show values in specificity format these processes are performed using the CASE command or with other functions on the selection field list, mean without updating. In such cases, we can change our format to any format and anytime with changing functions. As dynamic fields.
For example:
select id, lpad(id::text, 6, '0') as format_id from test.test_table1
order by id
Result:
id format_id
-------------
1 000001
2 000002
3 000003
4 000004
5 000005
Maybe you really need an UPDATE, so I wrote a sample query for an UPDATE command too.
update test.test_table1
set
id = lpad(id::text, 6, '0');
I need to add a row of sums as the last row of the table. For example:
book_name | some_row1 | some_row2 | sum
---------------+---------------+---------------+----------
book1 | some_data11 | some_data12 | 100
book2 | some_data21 | some_data22 | 300
book3 | some_data31 | some_data32 | 500
total_books=3 | NULL | NULL | 900
How can I do this? (T-SQL)
You can use union all :
select book_name, some_row1, some_row2, sum
from table t
union all
select cast(count(*) as varchar(255)), null, null, sum(sum)
from table t;
However, count(*) will give you no of rows available in table, if the book_name has null value also, then you need count(book_name) instead of count(*).
Try with ROLLUP
SELECT CASE
WHEN (GROUPING([book_name]) = 1) THEN 'total_books'
ELSE [book_name] END AS [book_name],some_row1, some_row2
,SUM(]sum]) as Total_Sales
From Before
GROUP BY
[book_name] WITH ROLLUP
I find that grouping sets is much more flexible than rollup. I would write this as:
select coalesce(book_name,
replace('total_books=#x', '#x', count(*))
) as book_name,
col2, col3, sum(whatever)
from t
group by grouping sets ( (book_name), () );
Strictly speaking, the GROUPING function with a CASE is better than COALESCE(). However, NULL values on the grouping keys is quite rare.
I am working on a SQL query where I have a rather huge data-set. I have the table data as mentioned below.
Existing table :
+---------+----------+----------------------+
| id(!PK) | name | Date |
+---------+----------+----------------------+
| 1 | abc | 21.03.2015 |
| 1 | def | 22.04.2015 |
| 1 | ajk | 22.03.2015 |
| 3 | ghi | 23.03.2015 |
+-------------------------------------------+
What I am looking for is an insert query into an empty table. The condition is like this :
Insert in an empty table where id is common, count of names common to an id for march.
Output for above table would be like
+---------+----------+------------------------+
| some_id | count | Date |
+---------+----------+----------------------+
| 1 | 2 | 21.03.2015 |
| 3 | 1 | 23.03.2015 |
+-------------------------------------------+
All I have is :
insert into empty_table values (some_id,count,date)
select id,count(*),date from existing_table where id=1;
Unfortunately above basic query doesn't suit this complex requirement.
Any suggestions or ideas? Thank you.
Udpated query
insert into empty_table
select id,count(*),min(date)
from existing_table where
date >= '2015-03-01' and
date < '2015-04-01'
group by id;
Seems you want the number of unique names per id:
insert into empty_table
select id
,count(distinct name)
,min(date)
from existing_table
where date >= DATE '2015-03-01'
and date < DATE '2015-04-01'
group by id;
If I understand correctly, you just need a date condition:
insert into empty_table(some_id, count, date)
select id, count(*), min(date)
from existing_table
where id = 1 and
date >= date '2015-03-01' and
date < date '2015-04-01'
group by id;
Note: the list after the table name contains the columns being inserted. There is no values keyword when using insert . . . select.
insert into empty_table
select id, count(*) as mycnt, min(date) as mydate
from existing_table
group by id, year_month(date);
Please use function provided by your RDBMS obtaining date part containing only year and month as far as you did not provide the RDBMS version and the date processing functionality varies wildly between them.
I have a table which is structured like this:
+-----+-------------+-------------------------+
| id | name | timestamp |
+-----+-------------+-------------------------+
| 1 | someName | 2016-04-20 09:41:41.213 |
| 2 | someName | 2016-04-20 09:42:41.213 |
| 3 | anotherName | 2016-04-20 09:43:41.213 |
| ... | ... | ... |
+-----+-------------+-------------------------+
Now, I am trying to create a query, which selects all timestamps since time x and count the amount of times the same name occurs in the result.
As an example, if we would apply this query to the table above, with 2016-04-20 09:40:41.213 as the date from which on it should be counted, the result should look like this:
+-------------+-------+
| name | count |
+-------------+-------+
| someName | 2 |
| anotherName | 1 |
+-------------+-------+
What I have accomplished so far is the following query, which gives me the the names, but not their count:
WITH screenshots AS
(
SELECT * FROM SavedScreenshotsLog
WHERE timestamp > '2016-04-20 09:40:241.213'
)
SELECT s.name
FROM SavedScreenshotsLog s
INNER JOIN screenshots sc ON sc.name = s.name AND sc.timestamp = s.timestamp
ORDER BY s.name
I have browsed through stackoverflow but was not able to find a solution which fits my needs and as I am not very experienced with SQL, I am out of ideas.
You mention one table in your question, and then show a query with two tables. That makes it hard to follow the question.
What you are asking for is a simple aggregation:
SELECT name, COUNT(*)
FROM SavedScreenshotsLog
WHERE timestamp > '2016-04-20 09:40:241.213'
GROUP BY name
ORDER BY COUNT(*) DESC;
EDIT:
If you want "0" values, you can use conditional aggregation:
SELECT name,
SUM(CASE WHEN timestamp > '2016-04-20 09:40:241.213' THEN 1 ELSE 0 END) as cnt
FROM SavedScreenshotsLog
GROUP BY name
ORDER BY cnt DESC;
Note that this will run slower because there is no filter on the dates prior to aggregation.
CREATE TABLE #TEST (name varchar(100), dt datetime)
INSERT INTO #TEST VALUES ('someName','2016-04-20 09:41:41.213')
INSERT INTO #TEST VALUES ('someName','2016-04-20 09:41:41.213')
INSERT INTO #TEST VALUES ('anotherName','2016-04-20 09:43:41.213')
declare #YourDatetime datetime = '2016-04-20 09:41:41.213'
SELECT name, count(dt)
FROM #TEST
WHERE dt >= #YourDatetime
GROUP BY name
I've posted the answer, because using the above query can generate errors in converting the string in where clause into a datetime, it depends on the format of the datetime.