I want to update a field based on a where IN () clause but i also want the update the rest of the values using WHERE NOT IN()..For example:
UPDATE TABLE SET COLUMN1 = X WHERE COLUMN2 IN (1,2,3)
UPDATE TABLE SET COLUMN1 = Y WHERE COLUMN2 NOT IN (1,2,3)
To simply put it ,is there a way to combine these two queries?
UPDATE
TABLE
SET
COLUMN1 = CASE WHEN COLUMN2 IN (1,2,3) THEN X ELSE Y END
Related
I have 2 tables name test and test_snapshop. in test table i am saving the current data and in test_snapshot i am saving older data. Now i need to do an update against some id values.theer is a chance that some ids exist in test and some in snapshot table.
I tried like this
update test
set column1=value,
column2=value,
column3=value
where column4 in(1,2,3)
union
update test_snapshot
set column1=value,
column2=value,
column3=value
where column4 in(1,2,3)
Both tables have same no and name of column.
The above query is not as expected. what I am doing wrong in this query. can any one help me in this.
I am new to postgresql.
Although I voted to close as a typo, you can express this in Postgres using a single statement. I might go for:
with ids as (
select *
from (values (1), (2), (3)) v(id)
),
t as (
update test
set column1 = value,
column2 = value,
column3 = value
where column4 in (select i.id from ids i)
)
update test_snapshot
set column1 = value,
column2 = value,
column3 = value
where column4 in (select i.id from ids i);
With this structure, you only need to list the id values once.
How can I set all rows of a column by manually typing the values?
My table has 3 rows, I want the column named mycolumn to have 3 values a, b and c (currently those values are NULL):
update mytable set mycolumn = ('a','b','c')
ORA-00907 missing right parenthesis
EDIT: my table is very simple, I have one column ID INT NOT NULL with values 1, 2, 3 and another column mycolumn with all NULL values and I want those values to become 'a' where ID = 1, 'b' where ID=2 etc.
EDIT2: I might have a huge amount of rows, so I want to avoid typing every single ID value where to replace mycolumn. Isn't it possible to match the ID values of 1 to 3 to the values 'a', 'b', 'c' in an automatic way, something like match(ID, ('a','b','c')) perhaps
I just want to replace all values of mycolumn by increasing order of ID. ID being strictly equivalent to what I call a row number in a matrix
EDIT3: I'd like a solution which would work in a general case with all sorts of values, not only the letters of the alphabet given here for simplicity. What if for example my values to replace in mycolumn are ('oefaihfoiashfe', 'fiaohoawdihoiwahopah', 'aefohdfaohdao')? However the ID row numbers will always be a sequence from 1 to N by 1.
Obviously, you should do this in a single update. Like this:
update mytable
set mycolumn = case id when 1 then 'a' when 2 then 'b' when 3 then 'c' end
;
More compact (but also more cryptic, and only works in Oracle, while case expressions are in the SQL standard):
update mytable
set mycolumn = decode(id, 1, 'a', 2, 'b', 3, 'c')
;
Note - this only works if there really are only three rows. If you have many more rows, make sure to add where id in (1, 2, 3) at the end. Otherwise all the OTHER values (in the other rows) will be updated to null!
You can try an update like the one below. This will update 1 > a, 2 > b, 3 > c, 4 > d, etc. When you reach ID 27, since there are no more letters, it will begin at a again and continue down the alphabet.
UPDATE mytable
SET mycolumn = CASE MOD (id, 26)
WHEN 0 THEN 'z'
ELSE CHR (MOD (id, 26) + 96)
END;
Update
To update based on any list of values, you can try an update statement like the one below. If you add a 4th item to the comma delimited list, ID 4 in mytable will be set to whatever you specified as the 4th value.
UPDATE mytable
SET mycolumn =
(SELECT COLUMN_VALUE
FROM (SELECT ROWNUM AS row_num, t.COLUMN_VALUE
FROM TABLE (
sys.odcivarchar2list ('oefaihfoiashfe',
'fiaohoawdihoiwahopah',
'aefohdfaohdao')) t)
WHERE row_num = id);
Hmmm . . . A row can only have one value. Perhaps something like this to assign random values:
update mytable
set mycolumn = (case floor(dbms_random.random * 3)
case 0 then 'a' case 1 then 'b' else 'c'
end)
if you want the 3 rows to have different values a, b and c then you will have to write 3 update statements.
update mytable set mycolumn = 'a' where id = 1;
update mytable set mycolumn = 'b' where id = 2;
update mytable set mycolumn = 'c' where id = 3;
I have multiple columns in my table that have a NULL value.
I want to replace all of the NULL values in this table with a 0.
Assuming all of you columns being of a numeric data type, you can do this:
UPDATE YourTable
SET Column1 = ISNULL(Column1,0),
Column2 = ISNULL(Column2,0),
Column3 = ISNULL(Column3,0),
Column4 = ISNULL(Column4,0)....
I am constructing an SQL statement with some parameters. Finally, an SQL statement is created like
"select * from table where column1 = "xyz"".
But I also need the rows which are filtered with this statement. In this case they're rows which are not "xyz" valued in column1. More specifically, I am looking for something like INVERSE(select * from table where ...). Is it possible?
Edit: My bad, I know I can do it with != or operator. Here the case is, select statement may be more complex (with some ANDs and equal, greater operators). Let's assume a table has A,B,C and my SQL statement brings only A as result. But I need B and C while I only have the statement which brings A.
select * from table where column1 != 'xyz' or column1 is null;
If you want the other ones, do it like this:
select * from table where column1 <> "xyz"
column1 <> (differs from) "xyz"
To check if something is no equal you can use <> or even !=
SELECT *
FROM yourTable
WHERE <> 'xyz'
OR
SELECT *
FROM yourTable
WHERE != 'xyz'
Many database vendors support (see list) both versions of the syntax.
If you're retrieving both result sets at about the same time, and just want to process the xyz ones first, you could do:
select *,CASE WHEN column1 = "xyz" THEN 1 ELSE 0 END as xyz from table
order by CASE WHEN column1 = "xyz" THEN 1 ELSE 0 END desc
This will return all of the rows in one result set. Whilst xyz = 1, these were the rows with column1 = 'xyz'.
It was :
"select * from table where rowId NOT IN (select rowId from table where column1 = "xyz")
I needed a unique rowId column to achieve this.
Im trying to do something like the following:
UPDATE table SET fieldA='valueA' WHERE id='id1', SET fieldB='valueB' WHERE id='id2';
But cant seem to get it to work. Is there a way of doing this, or will I need to use two separate SQL commands?
If you really need to do it in one statement, you can use this:
UPDATE table
SET fieldA = case when id = 'id1' then 'valueA' else fieldA end,
fieldB = case when id = 'id2' then 'valueB' else fieldB end
WHERE id in ('id1', 'id2');
But for clarity (and thus maintainability), it would be much better to use two statements.
This is best done as 2 different UPDATE statements, because you have 2 different WHERE clauses:
UPDATE table SET fieldA='valueA' WHERE id='id1'
UPDATE table SET fieldB='valueB' WHERE id='id2'
MERGE INTO YourTable
USING ( VALUES ( 'id1', 'valueA', NULL ),
( 'id2', NULL, 'valueB' ) )
AS source ( id, fieldA , fieldB )
ON YourTable.id = source.id
WHEN MATCHED THEN
UPDATE
SET fieldA = COALESCE(source.fieldA, YourTable.fieldA),
fieldB = COALESCE(source.fieldB, YourTable.fieldB);
You'll need to use 2 separate SQL-statements because the set operator works on the whole resultset that's filtered by the where-clause.
UPDATE table SET fieldA='valueA' WHERE id='id1'; UPDATE table SET fieldB='valueB' WHERE id='id2';
UPDATE table SET fieldA='valueA',fieldB='valueB' WHERE id in ('id1','id2')