Can I use a case statement in Set Column? I have multiple columns that need to be updated but the statement is quite similar. The only difference is what I'm selecting.
UPDATE TABLE1 A
SET A.COLUMN2 = (SELECT....
I want to update column2 to Column1 without repeating the same block of code.
Note: I'm using LISTAGG
Is there any way I could distinct both of the columns without trying to separate it in one query the make a subquery
I'm using this query and I know that listagg don't have the capabilities to distinct unless you distinct it first before using listagg
SELECT LISTAGG(COLUMN1 , ', ') WITHIN GROUP (ORDER BY COLUMN1) AS COLUMN1 ,
LISTAGG(COLUMN2 , ', ') WITHIN GROUP (ORDER BY COLUMN2) AS COLUMN1
FROM (SELECT COLUMN1 , COLUMN2 FROM TABLE2 B
WHERE A.COLUMN3 = B.COLUMN3
GROUP BY COLUMN1 , COLUMN2);
COLUMN1 COLUMN2
EGG PIE
EGG BREAD
Expected output
COLUMN1 COLUMN2
EGG PIE; BREAD
Do you mean
UPDATE table1
SET (column1, column2 ...) = (SELECT col1, col2 ...)
Related
I am trying to get a new column with a concatenation of all distinct row values. This aggregation would be based on other columns.
I have tried the following but I get the same values repeated in the new column (A1, A1, A4). I need the concatenation to be distinct.
SELECT
STRING_AGG(COLUMN1, ', ') AS COLUMN1_ALIAS
,COLUMN2
,COLUMN3
,COLUMN4
FROM TABLE
GROUP BY COLUMN2 ,COLUMN3 ,COLUMN4
It looks like you want windowing rather than aggregation. Unfortunately, string_agg does not support over() in SQL Server ; neither does it support distinct in its aggregated form.
We could work around it with subqueries ; it is probably more efficient to deduplicate and pre-compute the aggregates first, then join with the original table:
select t.*, x.column1_alias
from mytable t
inner join (
select column2, column3, column4, string_agg(column1, ', ') as column1_alias
from (select distinct column1, column2, column3, column4 from mytable) t
group by column2, column3, column4
) x on x.column2 = t.column2 and x.column3 = t.column3 and x.column4 = t.column4
Side note : in a database that supports both over() and distinct on string aggregation, the query would phrase as:
select t.*,
string_agg(distinct column4, ', ')
over(partition by column2, column3, column4) as column1_alias
from mytable t
The table looks like
column1 column2 column3
400196 2021-07-06 33
400196 2021-07-06 33
400196 2021-08-16 33
I want to get the sum of column3 values based on grouping of column 1 but the duplicate values of date should not be added
The desired output is:
column1 column3
400196 66
The query I wrote is
select sum(column3)
from table_name
group by column1
But this gives me result 99
You can remove duplicate values in a subquery:
select t.column1, sum(t.column3)
from (select distinct t.column1, t.column2, t.column3
from t
) t
group by t.column1;
Note: This sort of problem can arise when you are joining tables together. Removing duplicates may not always be the right solution. Often it is better to do the calculation before joining, so you don't have duplicate values to deal with.
You could use a two step process here, first remove duplicates, then aggregate and sum:
SELECT column1, SUM(column3) AS column3
FROM (SELECT DISTINCT column1, column2, column3 FROM yourTable) t
GROUP BY column1;
Demo
I have below query
SELECT ROW_NUMBER() OVER ( PARTITION BY COLUMN1, COLUMN2, COLUMN3 ORDER BY COLUMN1, COLUMN2) AS ROW_NUM, COLUMN1, COLUMN2, COLUMN3
FROM (SUBQUERY)
GROUP BY COLUMN1, COLUMN2, COLUMN3
OUTPUT of above query:-
I need to perform something equivalent to
IF (COLUMN2 == 'PQR' AND COLUMN3 IS NOT NULL)
THEN
"Delete whole partition from output having value A3 in column1"
Explaination:-
If COLUMN2 is having value PQR and COLUMN3 is having any DATE_TIME (i.e. NOT NULL) then all the corresponding COLUMN1 value should not be present in output of query.
OUTPUT required is:-
I tried to be as clear as I can be. Let me know if I need to clarify my question more.
NOTE:- I want to remove those rows only from output of the query not from actual table.
If you are doing this using a subquery, then you might want to use window functions:
SELECT s.*
FROM (SELECT ROW_NUMBER() OVER ( PARTITION BY COLUMN1, COLUMN2, COLUMN3 ORDER BY COLUMN1, COLUMN2) AS ROW_NUM,
COLUMN1, COLUMN2, COLUMN3,
COUNT(CASE WHEN COLUMN2 = 'PQR' THEN COLUMN3 END) OVER (PARTITION BY COLUMN1) as cnt
FROM (SUBQUERY)
GROUP BY COLUMN1, COLUMN2, COLUMN3
) s
WHERE cnt = 0;
This counts the number of COLUMN3 values where COLUMN2 = 'PQR' over all each COLUMN1. It then returns only the rows where this count is 0.
The advantage of this approach is that it only evaluates the subquery once -- that can be a performance win (over NOT EXISTS) if it is complicated.
If you want a select query then you can use NOT EXISTS:
SELECT * FROM YOUR_TABLE T1
WHERE NOT EXISTS (SELECT 1 FROM YOUR_TABLE T2
WHERE T1.COLUMN1 = T2.COLUMN1
AND T2.COLUMN2 = 'PQR' AND T2.COLUMN3 IS NOT NULL);
You can use the EXISTS to delete such records as follows:
DELETE FROM YOUR_TABLE T1
WHERE EXISTS (SELECT 1 FROM YOUR_TABLE T2
WHERE T1.COLUMN1 = T2.COLUMN1
AND T2.COLUMN2 = 'PQR' AND T2.COLUMN3 IS NOT NULL);
I have a table say,
column1 column2
a apple
a ball
a boy
b apple
b eagle
b orange
c bat
c ball
c cork
Now I would like to fetch column1 based on the rows that doesn't contain 'apple' and also ignore values in column1 if any of the rows have 'apple' in it. So in the table above only 'C' must be retured.
I am kind of new to Oracle SQL and I know Select column1 from table where column2 != 'apple' will not work. I need some help with this please.
You could use DISTINCT with NOT IN in following:
QUERY 1 using NOT IN
select distinct col1
from t
where col1 not in (select col1 from t where col2 = 'Apple')
QUERY 2 using NOT EXISTS
As per #jarlh comment you could use NOT EXISTS in following:
select distinct col1
from #t t1
where not exists (select 1 from #t t2 where col2 = 'Apple' and t1.col1 = t2.col1)
SAMPLE DATA
create table t
(
col1 nvarchar(60),
col2 nvarchar(60)
)
insert into t values
('a','apple')
,('a','ball')
,('a','boy')
,('b','apple')
,('b','eagle')
,('b','orange')
,('c','bat')
,('c','ball')
,('c','cork')
Assuming that column1 is NOT NULL you could use:
SELECT DISTINCT t.column1
FROM table_name t
WHERE t.column1 NOT IN (SELECT column1
FROM table_name
WHERE column2 = 'apple');
LiveDemo
To get all columns and rows change DISTINCT t.column1 to *.
Select * from tbl
Left join (
Select column1 from tbl
Where column2 like '%apple%'
Group by column1
) g on tbl.colum1 = g.column1
Where g.column1 is null
Seems to me that you need to find a summary of all colum1 values that have any reference to apple. Then list the rows that have no match to the summary list (g)
If I understand well, you need the values af column1 such that in your table does not exist a row with the same value of column1 and 'apple' in column2; you can translate this in SQL with:
Select column1
from your_table t
where not exists (
select 1
from your_table t2
where t2.column1 = t1.column1
and t2.column2= 'apple'
)
This is only one of the possible ways to get your result, soyou can rewrite it in many ways; I believe this way of writing is similar enough to the logics to clearly explain how a logic could be written in plain SQL.
I'm trying to isolate a problem with a violation of a unique key index. I'm pretty certain that the cause is resulting from columns that have the same value in 3 columns not having the same value in the 4th (when they should). As an example...
Key Column1 Column2 Column3 Column4
1 A B C D
2 A B C D
3 A B C D
4 A B C Z
I basically want to select column 4, or some way to let me identify column 4. I know it's a matter of using aggregrate functions but I'm not very familiar with them. Can anyone assist on a way to select Key, Column4 for rows that have a different column 4 value and the same column 1-3 values?
This is what you want:
select column1, column2, column3
from t
group by column1, column2, column3
having min(column4) <> max(column4)
Once you get the right values for the first three columns, you can join back in to get the specific rows.
Or, you can use window functions like this:
select t.*
from (select t.*, min(column4) over (partition by column1, column2 column3) as min4,
max(column4) over (partition by column1, column2 column3) as max4
from t
) t
where min4 <> max4;
If NULL is a valid "other" value that you want to count, you will need additional logic for that.
If you want to get all columns, then (it could be simpler if windowed count supported distinct but it's not):
with cte1 as (
select distinct * from Table1
), cte2 as (
select
*,
count(column4) over(partition by column1, column2, column3) as cnt
from cte1
)
select * from cte2 where cnt > 1;
if you want just to select key:
select
column1, column2, column3
from Table1
group by column1, column2, column3
having count(distinct column4) > 1
sql fiddle demo