I need a query but I have a criteria depends on situation. As an example :
Lets have a table named table1 that has column named column1 and
table2 that has column named column2
In the query in where clause, I need to join this table1 with table2 by column1 and column2 columns. But, I need to do like
if
column1 = 'x' then my criteria must be column1 = column2
else
column1 != 'x'
How I can write this where clause in Oracle?
Thank you for your answer.
Try this
WHERE (Column1 != 'x' OR (Column1 = 'x' AND column1 = column2))
Just use OR condition like this one:
WHERE (Column1 <> 'x' OR column1 = column2)
(This is normal SQL syntax. Don't know if there is any change in syntax of Oracle. But you can try this logic)
EDIT: (From OP's comment in my answer)
You can do that something like this one:
WHERE (column2 != (Select col from table3) OR column1 = 'x')
Or
WHERE (column2 != (Select col from table3) OR column1 = (Select col from table3))
Related
I have an SQL select statement with many columns. However I want to exclude an entire row if certain column combinations exist.
My query looks something like this:
SELECT COLUMN1, COLUMN2, COLUMN3
FROM TABLE
WHERE NOT (COLUMN2 = 'A' AND COLUMN3 = 'B')
AND NOT (COLUMN2= 'B' AND COLUMN3 = 'C')
.
.
.
This doesn't seem to work, I am getting a "missing expression" error. What is the correct way to exclude entire rows when column combinations match certain conditions?
Thank you!
Since a row can only match one of those conditions at one time, you should be using OR:
SELECT COLUMN1, COLUMN2, COLUMN3
FROM YourTable
WHERE NOT (
( COLUMN2 = 'A' AND COLUMN3 = 'B' )
OR
( COLUMN2= 'B' AND COLUMN3 = 'C' )
)
db<>fiddle here
Let's say I have the following table (named table_1):
Column1 Column2 Column3
A 123 'ABCDE'
B 333 'FGHIJ'
C 444 'KLMNO'
and I have another table, like this one (named table_2):
Column4
'BCD'
'FGH'
Now, I want to filter table_1 using table_2. However, as you can see Column4 doesn't contain the full name of Column3, just part of it. I thought about exporting Column4, putting it in Notes (or any other text app) and doing something like:
select * from table_1 where Column3 like '%BCD%' or Column3 like '%FGH%'
But I was wondering if there is another way, smarter.
You can use exists and like:
select t1.*
from table_1 t1
where exists (
select 1 from table_2 t2 where t1.column3 like '%' || t2.column4 || '%'
)
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 ...)
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.
column1 column2
x y
y x
how does one go about eliminating such duplicates? or at worst selecting just one of those tuples?
It's become kind of a mainstream habit among question askers to withhold the information which RDBMS we are dealing with. In response: this is tested and works with a certain RDBMS I am not inclined to name. Go figure!
DELETE FROM tbl a
USING tbl b
WHERE (a.x, a.y) = (b.y, b.x)
AND a.y > a.x -- keep the one dupe with the biggest x
Assuming there are no dupes with x = y. This would be an ordinary duplicate anyway.
One approach is to identify only the valid rows e.g.
SELECT column1, column2
FROM T
WHERE column1 <= column2
UNION
SELECT column2 AS column1, column1 AS column2
FROM T
WHERE column1 > column2;
...then delete rows that aren't in the set of valid rows:
DELETE
FROM T
WHERE NOT EXISTS (
SELECT *
FROM (
SELECT column1, column2
FROM T
WHERE column1 <= column2
UNION
SELECT column2 AS column1, column1 AS column2
FROM T
WHERE column1 > column2
) AS DT1
WHERE DT1.column1 = T.column1
AND DT1.column2 = T.column2
);
Alternatively, the DELETE may be simplified to target only the invalid rows:
DELETE
FROM T
WHERE column1 > column2
AND EXISTS (
SELECT *
FROM T AS T1
WHERE T1.column1 = T.column2
AND T1.column2 = T.column1
);