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)....
Related
I'm writing a query to update a table. The table has many fields among which there are 3 fields: column1, column2, column3 each of which can be null.
The data is loaded every day. On day 1 a row can come in which
column1 is null,
column2 is not null
column3 is null.
The next day there may be a row where
column1 is not null,
column2 is null,
column3 is null.
The idea is to insert new rows, and those rows which are identical to previously uploaded ones, but which column1, column2, column3 change are not inserted, but updated.
I tried to write a query to update all three fields at once. But in case described above, I will change not null to null.
Does anyone know a way to update any of the fields in a single update query without writing null there?
for example:
update table2 upt
set column1 = n.column1,
column2 = n.column2,
column3 = n.column3
from (select new.column1, new.column2, new.column3, new.column4, new.column5
from table1 new
where new.column4 in (select old.column4 from table2 old
where old.column5 = new.column5
and (old.column1 is null or old.column2 is null or old.column3 is null)
and (new.column1 is not null or new.column2 is not null and new.column3 is not null) n
where upt.date_fielad = '2022-01-01'
and upt.column4 = n.column4
and upt.column5 = n.column5
and (upt.column1 <> n.column1
or upt.column2 <> n.column2
or upt.column3 <> n.column3)
How I can change this query to not update not null fields null?
I'm just starting with SQL with no training but the job suddenly requires it. So thank you in advance for any help.
Let's say I have a query that returns 3 columns. Some of the cells in column 3 are empty and I would like to fill them in with values based on column1.
example:
CASE column1 = 'Individual' then Column3 should show 'Individual' not empty, but if column1 = 'group' them column3 needs to show "group" else no change.
SELECT column1, column2, column3,
CASE
WHEN column1 = 'Individual' THEN Column3 = 'Individual'
WHEN column1 = "Group' THEN comlumn3 = 'Group'
END
FROM tablename
If you only want to select data and not change the table values you can use case as you tried:
SELECT column1, column2,
CASE
WHEN column3 IS NULL THEN Column1
ELSE column3
END as column3
FROM tablename
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.
I am trying to select the earlier date/time from a two given columns. However, I am running into issues if one of the two columns have a null value.
my thought is
select case when dateTime1 < datetime2 then column1 else column2
end as EarlierDate
from table
However, using the above method will always return null values regardless how I change the greater or smaller sign.
You can have:
Select Case When Column1 is null then Column2 when Column2 is Null then Column1 When Column1 > Column2 Then Column2 When Column1 < Column2 Then Column1 End As EarlierDate From TableName
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