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I would like to check for several columns that: For each column the value is either NULL or the same for all records.
For example, the condition holds for the following table
+------+------+------+------+
| Col1 | Col2 | Col3 | Col4 |
+------+------+------+------+
| A | B | NULL | NULL |
| NULL | B | C | NULL |
| A | B | C | NULL |
+------+------+------+------+
How can I do that, preferably with one query?
EDIT:
An alternative question would be: How can I sum the distinct values of each of the selected columns
You can check if the distinct number of values in each individual column is less than or equal to 1:
SELECT COUNT(DISTINCT Col1) <= 1 ok1,
COUNT(DISTINCT Col2) <= 1 ok2,
COUNT(DISTINCT Col3) <= 1 ok3,
COUNT(DISTINCT Col4) <= 1 ok4
FROM tablename;
Or, you can get a result for the the whole table:
SELECT MAX(
COUNT(DISTINCT Col1),
COUNT(DISTINCT Col2),
COUNT(DISTINCT Col3),
COUNT(DISTINCT Col4)
) <= 1 ok
FROM tablename;
See the demo.
We use software to store combinations of financial elements. Those elements are allowed in certain combinations. Exceptions of these combinations are SQL-like statements in the front-end, and are saved as numerical values in a database table like the following example:
+------+------+------+------+------+
| Col1 | Col2 | Col3 | Col4 | Col5 |
+------+------+------+------+------+
| 1 | 2 | 4 | 5 | 1 |
+------+------+------+------+------+
| -1 | 2 | 6 | 4 | 5 |
+------+------+------+------+------+
| 1 | 2 | 5 | 7 | 1 |
+------+------+------+------+------+
I would like to translate those numerical values back to a SQL-statement like the following example:
+------+-----------+------+-----------+------+-----------+------+-----------+------+-----------+
| Col1 | Col1Trans | Col2 | Col2Trans | Col3 | Col3Trans | Col4 | Col4Trans | Col5 | Col5Trans |
+------+-----------+------+-----------+------+-----------+------+-----------+------+-----------+
| 1 | ( | 2 | SELECT | 4 | CODE | 5 | LIKE | 1 | * |
+------+-----------+------+-----------+------+-----------+------+-----------+------+-----------+
| -1 | | 2 | SELECT | 6 | NUMBER | 4 | = | 5 | AND |
+------+-----------+------+-----------+------+-----------+------+-----------+------+-----------+
| 1 | ( | 2 | SELECT | 5 | TOOL | 7 | <> | 1 | * |
+------+-----------+------+-----------+------+-----------+------+-----------+------+-----------+
The numerical values differ in each column so I can only imagine the use of a lot of case...when statements which I doubt will be efficiënt. I don't want to create tables to hold the translation values. Are there ways to do this with arrays?
Are there any code samples to easily loop through table/columns and translate the contents of it?
You can use below code and add more case statement as per the requirement.
SELECT Col1
,CASE
WHEN Col1 = 1 THEN '('
ELSE '' END AS Col1Trans
,Col2
,CASE
WHEN Col2 = 2 THEN 'SELECT'
END AS Col2Trans
,Col3
,CASE
WHEN Col3 = 4 THEN 'CODE'
WHEN Col3 = 6 THEN 'NUMBER'
WHEN Col3 = 5 THEN 'TOOL'
END AS Col3Trans
,Col4
,CASE
WHEN Col4 = 5 THEN 'LIKE'
WHEN Col4 = 4 THEN '='
WHEN Col4 = 7 THEN '<>'
END AS Col4Trans
,Col5
,CASE
WHEN Col5 = 1 THEN '*'
WHEN Col5 = 5 THEN 'AND'
END AS Col5Trans
The best way to avoid so many case when and decode and etc is to use with as clause as following:
With col1trans (value, translation) as
(Select 1, '(' from dual union all
Select -1, null from dual),
Col2trans (value, translation) as
(Select 2, 'SELECT' from dual)
..
... till col5trans
Select m.col1, t1.translation as col1trans,
.... till m.col5, t5.translation
From your_table m join col1trans t1 m.col1=t1.value
join col2trans t2 m.col2=t2.value
... till col5trans
Cheers!!
I have three tables in SQL Server with following structure:
col1 col2 a1 a2 ... an,
col1 col2 b1 b2 ... bn,
col1 col2 c1 c2 ... cn
The two first records are the same, col1 and col2, however the tables have different lengths.
I need to select the column names of the tables and the result I'm trying to achieve is the followig:
col1, col2, a1, b1, c1, a2, b2, c2 ...
Is there a way to do it?
It's possible but result's is combined into single column of three table tables.
For example
SELECT A.col1 +'/' +B.col1 +'/' + C.col1 As Col1 ,
A.col2 +'/' +B.col2 +'/' + C.col2 As col2 ,a1, b1, c1, a2, b2, c2 ,
* FROM A
INNER JOIN B
ON A.ID =B.ID
INNER JOIN C
ON C.ID = B.ID
SQL-Server is not the right tool to create a generic resultset. The engine needs to know what's coming out in advance. Well, you might try to find a solution with dynamic SQL...
I want to suggest two different approaches.
Both would work with any number of tables, as long as all of them have the columns col1 and col2 with appropriate types.
Let's create a simple mokcup scenario before:
DECLARE #mockup1 TABLE(col1 INT,col2 INT,SomeMore1 VARCHAR(100),SomeMore2 VARCHAR(100));
INSERT INTO #mockup1 VALUES(1,1,'blah 1.1','blub 1.1')
,(1,2,'blah 1.2','blub 1.2')
,(1,100,'not in t2','not in t2');
DECLARE #mockup2 TABLE(col1 INT,col2 INT,OtherType1 INT,OtherType2 DATETIME);
INSERT INTO #mockup2 VALUES(1,1,101,GETDATE())
,(1,2,102,GETDATE()+1)
,(1,200,200,GETDATE()+200);
--You can add as many tables as you need
A very pragmatic approach:
Try this simple FULL OUTER JOIN:
SELECT *
FROM #mockup1 m1
FULL OUTER JOIN #mockup2 m2 ON m1.col1=m2.col1 AND m1.col2=m2.col2
--add more tables here
The result
+------+------+-----------+-----------+------+------+------------+-------------------------+
| col1 | col2 | SomeMore1 | SomeMore2 | col1 | col2 | OtherType1 | OtherType2 |
+------+------+-----------+-----------+------+------+------------+-------------------------+
| 1 | 1 | blah 1.1 | blub 1.1 | 1 | 1 | 101 | 2019-03-08 10:53:20.257 |
+------+------+-----------+-----------+------+------+------------+-------------------------+
| 1 | 2 | blah 1.2 | blub 1.2 | 1 | 2 | 102 | 2019-03-09 10:53:20.257 |
+------+------+-----------+-----------+------+------+------------+-------------------------+
| 1 | 100 | not in t2 | not in t2 | NULL | NULL | NULL | NULL |
+------+------+-----------+-----------+------+------+------------+-------------------------+
| NULL | NULL | NULL | NULL | 1 | 200 | 200 | 2019-09-24 10:53:20.257 |
+------+------+-----------+-----------+------+------+------------+-------------------------+
But you will have to deal with non-unique column names... (This is the moment, where a dynamically created statement can help).
A generic approach using container type XML
Whenever you do not know the result in advance, you can pack the result in a container. This allows a clear structure on the side of your RDBMS and shifts the troubles how to deal with this set to the consumer.
The cte will read all existing pairs of col1 and col2
Each table's row(s) for the pair of values is inserted as XML
Pairs not existing in any of the tables show up as NULL
Try this out
WITH AllDistinctCol1Col2Values AS
(
SELECT col1,col2 FROM #mockup1
UNION ALL
SELECT col1,col2 FROM #mockup2
--add all your tables here
)
SELECT col1,col2
,(SELECT * FROM #mockup1 x WHERE c1c2.col1=x.col1 AND c1c2.col2=x.col2 FOR XML PATH('row'),TYPE) AS Content1
,(SELECT * FROM #mockup2 x WHERE c1c2.col1=x.col1 AND c1c2.col2=x.col2 FOR XML PATH('row'),TYPE) AS Content2
FROM AllDistinctCol1Col2Values c1c2
GROUP BY col1,col2;
The result
+------+------+-----------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------+
| col1 | col2 | Content1 | Content2 |
+------+------+-----------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------+
| 1 | 1 | <row><col1>1</col1><col2>1</col2><SomeMore1>blah 1.1</SomeMore1><SomeMore2>blub 1.1</SomeMore2></row> | <row><col1>1</col1><col2>1</col2><OtherType1>101</OtherType1><OtherType2>2019-03-08T11:03:49.877</OtherType2></row> |
+------+------+-----------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------+
| 1 | 2 | <row><col1>1</col1><col2>2</col2><SomeMore1>blah 1.2</SomeMore1><SomeMore2>blub 1.2</SomeMore2></row> | <row><col1>1</col1><col2>2</col2><OtherType1>102</OtherType1><OtherType2>2019-03-09T11:03:49.877</OtherType2></row> |
+------+------+-----------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------+
| 1 | 100 | <row><col1>1</col1><col2>100</col2><SomeMore1>not in t2</SomeMore1><SomeMore2>not in t2</SomeMore2></row> | NULL |
+------+------+-----------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------+
| 1 | 200 | NULL | <row><col1>1</col1><col2>200</col2><OtherType1>200</OtherType1><OtherType2>2019-09-24T11:03:49.877</OtherType2></row> |
+------+------+-----------------------------------------------------------------------------------------------------------+-----------------------------------------------------------------------------------------------------------------------+
I have a table in Oracle database, which have 40 columns.
I know that if I want to do a group by query, all the columns in select must be in group by.
I simply just want to do:
select col1, col2, col3, col4, col5 from table group by col3
If I try:
select col1, col2, col3, col4, col5 from table group by col1, col2, col3, col4, col5
It does not give the required output.
I have searched this, but did not find any solution. All the queries that I found using some kind of Add() or count(*) function.
In Oracle is it not possible to simply group by one column ?
UPDATE:
My apologies, for not being clear enough.
My Table:
+--------+----------+-------------+-------+
| id | col1 | col2 | col3 |
+--------+----------+-------------+-------+
| 1 | 1 | some text 1 | 100 |
| 2 | 1 | some text 1 | 200 |
| 3 | 2 | some text 1 | 200 |
| 4 | 3 | some text 1 | 78 |
| 5 | 4 | some text 1 | 65 |
| 6 | 5 | some text 1 | 101 |
| 7 | 5 | some text 1 | 200 |
| 8 | 1 | some text 1 | 200 |
| 9 | 6 | some text 1 | 202 |
+--------+----------+-------------+-------+
and by running following query:
select col1, col2, col3 from table where col3='200' group by col1;
I will get the following desired Output:
+--------+----------+-------------+-------+
| id | col1 | col2 | col3 |
+--------+----------+-------------+-------+
| 2 | 1 | some text 1 | 200 |
| 3 | 2 | some text 1 | 200 |
| 7 | 5 | some text 1 | 200 |
+--------+----------+-------------+-------+
Long comment here;
Yeah, you can't do that. Think about it... If you have a table like so:
Col1 Col2 Col3
A A 1
B A 2
C A 3
And you're grouping by only Col2, which will group down to a single row... what happens to Col1 and Col3? Both of those have 3 distinct row values.
How is your DBMS supposed to display those?
Col1 Col2 Col3
A? A 1?
B? 2?
C? 3?
This is why you have to group by all columns, or otherwise aggregate or concatenate them. (SUM(),MAX(), MIN(), etc..)
Show us how you want the results to look and I'm sure we can help you.
Edit - Answer:
First off, thanks for updating your question. Your query doesn't have id but your expected results do, so I will answer for each separately.
Without id
You will still need to group by all columns to achieve what you're going for. Let's walk through it.
If you run your query without any group by:
select col1, col2, col3 from table where col3='200'
You will get this back:
+----------+-------------+-------+
| col1 | col2 | col3 |
+----------+-------------+-------+
| 1 | some text 1 | 200 |
| 2 | some text 1 | 200 |
| 5 | some text 1 | 200 |
| 1 | some text 1 | 200 |
+----------+-------------+-------+
So now you want to only see the col1 = 1 row once. But to do so, you need to roll all of the columns up, so your DBMS knows what do to with each of them. If you try to group by only col1, you DBMS will through an error because you didn't tell it what to do with the extra data in col2 and col3:
select col1, col2, col3 from table where col3='200' group by col1 --Errors
+----------+-------------+-------+
| col1 | col2 | col3 |
+----------+-------------+-------+
| 1 | some text 1 | 200 |
| 2 | some text 1 | 200 |
| 5 | some text 1 | 200 |
| ? | some text 1?| 200? |
+----------+-------------+-------+
If you group by all 3, your DBMS knows to group together the entire rows (which is what you want), and will only display duplicate rows once:
select col1, col2, col3 from table where col3='200' group by col1, col2, col3
+----------+-------------+-------+
| col1 | col2 | col3 |
+----------+-------------+-------+
| 1 | some text 1 | 200 |
| 2 | some text 1 | 200 | --Desired results
| 5 | some text 1 | 200 |
+----------+-------------+-------+
With id
If you want to see id, you will have to tell your DBMS which id to display. Even if we group by all columns, you won't get your desired results, because the id column will make each row distinct (They will no longer group together):
select id, col1, col2, col3 from table where col3='200' group by id, col1, col2, col3
+--------+----------+-------------+-------+
| id | col1 | col2 | col3 |
+--------+----------+-------------+-------+
| 2 | 1 | some text 1 | 200 | --id = 2
| 3 | 2 | some text 1 | 200 |
| 7 | 5 | some text 1 | 200 |
| 8 | 1 | some text 1 | 200 | --id = 8
+--------+----------+-------------+-------+
So in order to group these rows, we need to explicitly say what to do with the ids. Based on your desired results, you want to choose id = 2, which is the minimum id, so let's use MIN():
select MIN(id), col1, col2, col3 from table where col3='200' group by col1, col2, col3
--Note, MIN() is an aggregate function, so id need not be in the group by
Which returns your desired results (with id):
+--------+----------+-------------+-------+
| id | col1 | col2 | col3 |
+--------+----------+-------------+-------+
| 2 | 1 | some text 1 | 200 |
| 3 | 2 | some text 1 | 200 |
| 7 | 5 | some text 1 | 200 |
+--------+----------+-------------+-------+
Final thought
Here were your two trouble rows:
+--------+----------+-------------+-------+
| id | col1 | col2 | col3 |
+--------+----------+-------------+-------+
| 2 | 1 | some text 1 | 200 |
| 8 | 1 | some text 1 | 200 |
+--------+----------+-------------+-------+
Any time you hit these, just think about what you want each column to do, one at a time. You will need to handle all columns any time you do grouping or aggregates.
id, you only want to see id = 2, which is the MIN()
co1, you only want to see distinct values, so GROUP BY
col2, you only want to see distinct values, so GROUP BY
col3, you only want to see distinct values, so GROUP BY
maybe analytic functions is what you need
try smth like this:
select col1, col2, col3, col4, col5
, sum(*) over (partition by col1) as col1_summary
, count(*) over () as total_count
from t1
if you google the article - you find thousands on examples
for example this
Introduction to Analytic Functions (Part 1)
Why do you want to GROUP BY , wouldn't you want to ORDER BY instead?
If you state an English language version of the problem you are trying to solve (i.e. the requirements) it would be easier to be more specific.
I guess,maybe you need upivot function
or post your specific final result you want
select col3, col_group
from table
UNPIVOT ( col_group for value in ( col1,col2,col4,col5))
SELECT * FROM table
WHERE id IN (SELECT MIN(id) FROM table WHERE col3='200' GROUP BY col1)
I have a table that looks like the first example.
I'm trying to write a MSSQL2012 statement that that will display results like the second example.
Basically I want null values instead of duplicate values in columns 1 and 2. This is for readability purposes during reporting.
This seems like it should be possible, but I'm drawing a blank. No amount of joins or unions I've written has rendered the results I need.
| Col1 | Col2 | Col3 |
+------+------+------+
| 1 | 2 | 4 |
| 1 | 2 | 5 |
| 1 | 3 | 6 |
| 1 | 3 | 7 |
+------+------+------+
| Col1 | Col2 | Col3 |
+------+------+------+
| 1 | 2 | 4 |
| Null | null | 5 |
| null | 3 | 6 |
| null | null | 7 |
+------+------+------+
I would do this with no subqueries at all:
select (case when row_number() over (partition by col1 order by col2, col3) = 1
then col1
end) as col1,
(case when row_number() over (partition by col2 order by col3) = 1
then col2
end) as col2,
col3
from t
order by t.col1, t.col2, t.col3;
Note that the order by at the end of the query is very important. The result set that you want depends critically on the ordering of the rows. Without the order by, the result set could be in any order. So, the query might look like it works, and then suddenly fail one day or on a slightly different set of data.
Using a common table expression with row_number():
;with cte as (
select *
, rn_1 = row_number() over (partition by col1 order by col2, col3)
, rn_2 = row_number() over (partition by col1, col2 order by col3)
from t
)
select
col1 = case when rn_1 > 1 then null else col1 end
, col2 = case when rn_2 > 1 then null else col2 end
, col3
from cte
without the cte
select
col1 = case when rn_1 > 1 then null else col1 end
, col2 = case when rn_2 > 1 then null else col2 end
, col3
from (
select *
, rn_1 = row_number() over (partition by col1 order by col2, col3)
, rn_2 = row_number() over (partition by col1, col2 order by col3)
from t
) sub
rextester demo: http://rextester.com/UYA17142
returns:
+------+------+------+
| col1 | col2 | col3 |
+------+------+------+
| 1 | 2 | 4 |
| NULL | NULL | 5 |
| NULL | 3 | 6 |
| NULL | NULL | 7 |
+------+------+------+