I have a table of the form
Col1 | Col2
-------------
A | C
B | A
C | X
D | A
E | NULL
If any element of Col1 is present in Col2, then It should be printed as
Element, YES.
If it is not present in Col2, then it needs to be printed as element, NO and if corresponding col2 value is NULL then it needs to be printed as element, NULL
So final output should look like
A YES
B NO
C YES
D NO
E NULL
I was able to write three individual queries for the same but am struggling with the moment on how to put them inside Case statements in SQL.
SELECT Col1 FROM table WHERE col1 IN (SELECT col2 FROM table)
Select col1 FROM table where Col2 is NULL
SELECT Col1 FROM table WHERE col1 NOT IN (SELECT col2 FROM table)
I tried putting them inside case statements
Select col1, Case
when (SELECT Col1 FROM table WHERE col1 IN (SELECT col2 FROM table))
then "YES"
when (Select col1 FROM table where Col2 is NULL)
then "NULL"
else
"NO"
But I was getting an error. How should I fix this?
I would expect the query to look like this:
select col1,
(case when col2 is null then NULL
when col1 in (select t2.col2 from t t2)
then 'YES'
else 'NO'
end)
from t;
Related
I want to get the distinct values from COL1 and it's COL3 value also but the condition is if COL1 = COl2 then it should pick the matching COL3 value otherwise pick the COL1 value if they are not same. I'm stuck in the logic, any help will be appreciated!
Please see the below image for more detail:
select DISTINCT COL1,
CASE WHEN COL1 = COL2 THEN COL3 END COL3 from TABLE1
WHERE COL1 IS NOT NULL;
Do a GROUP BY to get distinct COL1 values.
Use COALESCE() to return the COL3 value if there exists a COL1 = COL2 row, otherwise return the max COL3 value for the COL1. (Could use MIN() too, if that's better.)
select COL1,
COALESCE( MAX(CASE WHEN COL1 = COL2 THEN COL3 END), MAX(COL3) )
FROM table1
WHERE COL1 IS NOT NULL
GROUP BY COL1
use correlated subquery
select col1,col3
from TABLE1 a
where col2 in (select min(col2) from table1 b where a.col1=b.col1)
select distinct COL1, if(COL1 = COL2, COL3, COL1) as result
from table1
I think that you can join the table with itself and then use a join conditio to filter that out, then decide in select wether there was COL2 = COL1 and choose appropriate COL3:
SELECT DISTINCT a.COL1, CASE WHEN b.COL1 IS NULL THEN a.COL3 ELSE b.COL3 END as COL3
FROM TABLE1 a
LEFT JOIN TBALE2 b
on a.COL1 = b.COL2
and a.COL1 = b.COL1
This way you have on table a all the data, and on table b data if and only if COL1 matches with COL2. Then you select whichever COL3 is not null, prefarably the one from table b. There is Oracle function coalesce that does just that.
With a self join:
select distinct
t.col1,
case
when tt.col1 is null then t.col3
else tt.col3
end col3
from tablename t left join tablename tt
on tt.col1 = t.col1 and tt.col2 = t.col1
See the demo.
Results:
> COL1 | COL3
> ---: | :---
> 11 | ABC
> 12 | ABC
> 13 | BDG
> 14 | DEF
> 15 | CEG
I have a table like this:
Result Col1 Col2 Col3
-----------------------------
Row1 null 1 null
Row1 2 null null
Row1 null null 3
Row1 1 null null
Row1 null 2 null
Row1 null null 3
and I would like to get the result like
Result Col1 Col2 Col3
-----------------------------
Row1 2 1 3
Row1 1 2 3
How to get this done in the SQL Server table? I know that if I use the MAX of Col1, Col2, Col3 I will get only one row. But I need to get the two rows.
How can I do this?
This is tricky. You can assign a sequential value using row_number() to each value and then aggregate.
Your data lacks ordering -- SQL tables represent unordered sets. Assuming you have an ordering column and you have only one non-NULL value per row:
select t.result, max(col1) as col1, max(col2) as col2, max(col3) as col3
from (select t.*,
row_number() over (partition by case when col1 is not null then 1
when col2 is not null then 2
when col3 is not null then 3
order by ? -- the ordering column
) as seqnum
from t
) t
group by t.result, seqnum;
If you can have multiple non-NULL values per row, then the question is ill-defined. Ask another question and provide sample data and desired results.
I have a select query
Select col1,col2,col3
from table;
The table contains following rows
col1 col2 col3
A | B | C
B | A | C
C | B | C
I need to get the distinct result which contains a single combination A,B,C by comparing multiple columns.
Result Should be some thing like
col1 col2 col3
A | B | C
the order can be changed of result rows.
How can I achieve this ?
Please try out this, I am not sure about you proper requirement. But on sample data given above. I have came across this solution,
With CTE as
(
Select MIN(col1) as col1 from MyTable
)
Select * from CTE
cross apply
(
Select MIN(col2) as col2 from MyTable
where col2 <> CTE.col1
)as a
cross apply
(
Select MIN(col3) as col3 from MyTable
where col3 not in (CTE.col1,a.col2)
)as b
DEMO HERE
SELECT *
FROM table
WHERE (col1 = 'A' AND col2 = 'B' AND col3 = 'C')
You can also go with this below query if the number of column and the values are known.
The CASE statement is the closest to IF in SQL
SELECT
CASE
WHEN (col1 = 'A' and col2 = 'B' and col3='C') or (col1 = 'C' and col2 = 'A' and col3='B') or (col1 = 'B' and col2 = 'C' and col3='A' )
THEN 1
ELSE 0
END as RESULT, *
FROM table
From the result you can take the required output by checking the value of RESULT==1(integer)
If you want the result as a boolean value then do the CAST like ,
SELECT
CAST(
CASE
WHEN (col1 = 'A' and col2 = 'B' and col3='C') or (col1 = 'C' and col2 = 'A' and col3='B') or (col1 = 'B' and col2 = 'C' and col3='A' )
THEN 1
ELSE 0
END as RESULT_INT)
as RESUTL, *
FROM table
I am working on sql query with table structure like below
col1 col2 col3
1 nik NULL
1 nik1 NULL
1 NULL mah
1 NULL mah1
Now i want output like
col1 col2 col3
1 nik mah
1 nik1 mah1
So i want to merge null values if there is value in col2 or col3
How can i achieve this ??
EDIT :Main structure is if col2 has values then col3 will be null and if col3 has value then col2 will be null
So i want to reduce the total no of rows by filling up null values
Try this:
SELECT T1.Col1,T1.Col2,T2.Col3
FROM
(SELECT Col1,Col2,ROW_NUMBER()OVER(ORDER BY Col1) as RN
FROM TableName
WHERE Col2 IS NOT NULL) T1 FULL OUTER JOIN
(SELECT Col1,Col3,ROW_NUMBER()OVER(ORDER BY Col1) as RN
FROM TableName
WHERE Col3 IS NOT NULL) T2 ON T1.Col1=T2.Col1 AND T1.RN=T2.RN
See result in SQL Fiddle.
I have a table that I wish to find the first non-null value from 3 (and only 3) columns for each ID starting with Col1 then to Col2 then to Col3
Note: Col3 is NEVER NULL
ID Col1 Col2 Col3
------------------------------
1 A B X
2 NULL C X
3 NULL NULL X
4 D NULL X
To get the correct column for each value I use the following SQL Select
SELECT ID,
COALESCE(Col1, Col2, Col3) AS Col
FROM MyTable
which returns the following and works just fine
ID Col
-------------
1 A
2 C
3 X
4 D
What I want is a third column returned indicating which column the coalesce was successful on. The following is the result set that I wish to produce:
ID Col Source
-----------------------
1 A Col1
2 C Col2
3 X Col3
4 D Col1
Perhaps this will work?
SELECT ID,
COALESCE(Col1, Col2, Col3) AS Col,
CASE COALESCE(Col1, Col2, Col3)
WHEN Col1 THEN 'Col1'
WHEN Col2 THEN 'Col2'
WHEN Col3 THEN 'Col3'
ELSE 'Unknown'
END AS Source
FROM MyTable