I want to update columns of a table whose values are NULL and I want to do this for 5 rows, but I'm getting the error : missing SET keyword
I am running the query in oracle SQL developer
The query I'm using is
UPDATE top(5) table_name
set col1=value1,
col2=value2,
col3=value3 where col1=null;
Second query I used is
UPDATE table_name
set col1=value1,
col2=value2,
col3=value3 where col1=null and rownum<=5;
You can do this in below way:
UPDATE table_name
set (col1,col2,col3) = (select col1,col2,col3 from table_name where col1 is null and rownum<=5)
where col1 is null;
Related
I am trying to update two tables with a single statement like this
db2 update catentry, catentdesc
set catentry.buyable=0,
catentdesc.published=0
where catentry.catentry_id=catentdesc.catentry_id
and catentry.partnumber='some value'
but getting an error
How can I accomplish this?
Set DB2 CLP to autocommit OFF and use ; command terminator:
db2 +c -t
update catentry set buyable=0 where partnumber='some value';
update catentdesc set published=0 where catentry_id IN
(SELECT catentry_id FROM catentry where partnumber='some value');
commit;
Not sure why you want to do this in a single statement, but recent versions of DB2 for LUW (and, with some restrictions, DB2 for z/OS) support what is called data change table references that allow tricks like
WITH t1 (catentry_id) AS (
SELECT catentry_id FROM FINAL TABLE (
UPDATE catentry SET buyable = 0 WHERE partnumber = 'some value'
)
), t2 (catentry_id) AS (
SELECT catentry_id FROM FINAL TABLE (
UPDATE catentdesc SET published = 0 WHERE catentry_id = (
SELECT catentry_id FROM t1
)
)
) SELECT 1 FROM sysibm.sysdummy1
Note that the actual statement must be a SELECT from something, and UPDATE statements are also wrapped in their own SELECTs, but this is executed as a single statement.
I created a table and inserted 3 rows. Then I added a new column using alter. How can I add values to the column without using any null values?
Two solutions.
Provide a default value for the column. This value will be used initially for all existing rows. The exact syntax depends on your database, but will will usually look like ..
this:
ALTER TABLE YourTable
ADD YourNewColumn INT NOT NULL
DEFAULT 10
WITH VALUES;
Add the column with null values first. Then update all rows to enter the values you want.
Like so:
ALTER TABLE YourTable
ADD YourNewColumn INT NULL;
UPDATE YourTable SET YourNewColumn = 10; -- Or some more complex expression
Then, if you need to, alter the column to make it not null:
ALTER TABLE YourTable ALTER COLUMN YourNewColumn NOT NULL;
Why don't you use UPDATE statement:
UPDATE tablename SET column=value <WHERE ...>
WHERE is optional. For instance in T-SQL for table:
I can update column NewTestColumn by this statement:
UPDATE [dbo].[Table] SET [NewTestColumn] = 'Some value'
Suppose you have a Employee table with these columns Employee_ID, Emp_Name,Emp_Email initially. Later you decide to add Emp_Department column to this table. To enter values to this column, you can use the following query :
Update *Table_Name* set *NewlyAddedColumnName*=Value where *Columname(primary key column)*=value
Example update TblEmployee set Emp_Department='Marketing' where Emp_ID='101'
I think below SQL useful to you
update table_name set newly_added_column_name = value;
update table_name
set new_column=value
Update table_name set column_name = value where 'condition';
suppose emp is the table and Comm is the new column then fire the below query .
update emp set Comm=5000
For Microsoft SQL (T-SQL):
UPDATE TABLE_NAME SET COLUMN_NAME=10;
here 10 means it will set all values by default to 10
I am newbie to triggers... can anybody help me with a trigger?
I have Table:
Name | Number
I want to write a trigger when my table receives a query like
update MyTable
set Number = Number + 1
where Name = 'myname'
When this query is running, the trigger should update another table for example:
Update MyTable 2
set Column = 'something'
where Name = 'myname (above name)
Thank you very much !
You will need to write an UPDATE trigger on table 1, to update table 2 accordingly.
Be aware: triggers in SQL Server are not called once per row that gets updated - they're called once per statement, and the internal "pseudo" tables Inserted and Deleted will contain multiple rows, so you need to take that into account when writing your trigger.
In your case, I'd write something like:
-- UPDATE trigger on "dbo.Table1"
CREATE TRIGGER Table1Updated
ON dbo.table1 FOR UPDATE
AS
BEGIN
-- update table2, using the same rows as were updated in table1
UPDATE t2
SET t2.Column = 'something'
FROM dbo.Table2 t2
INNER JOIN Inserted i ON t2.ID = i.ID
END
GO
The trick is to use the Inserted pseudo table (which contains the new values after the UPDATE - it has the exact same structure as your table the trigger is written for - here dbo.Table1) in a set-based fashion - join that to your dbo.Table2 on some column that they have in common (an ID or something).
create a trigger on table 1 for update:
CREATE TRIGGER dbo.update_trigger
ON table1
AFTER UPDATE
AS
BEGIN
DECLARE #Name VARCHAR(50)
SELECT #Name=Name FROM INSERTED
Update MyTable 2
SET Column = 'something'
WHERE Name = #Name
END
GO
try this ;)
I know i want to use an update statement but im having trouble with the structure of the query
The first of the following 2 SQL statements will create the new column in the table, and the second, update statement will populate the new column from the old column.
alter table Table1 add newColumn char(32);
update table1 set newColumn=oldColumn;
commit;
You can't create a new column using an update, you have to do that first. Then it's just as simple as:
update TheTable set NewColumn = OldColumn
UPDATE table
SET column2 = column1
update table_name set column_to_be_changed = existing column
If there's:
IF UPDATE (col1)
...in the SQL server trigger on a table, does it return true only if col1 has been changed or been updated?
I have a regular update query like
UPDATE table-name
SET col1 = 'x',
col2 = 'y'
WHERE id = 999
Now what my concern is if the "col1" was 'x' previously then again we updated it to 'x'
would IF UPDATE ("col1") trigger return True or not?
I am facing this problem as my save query is generic for all columns, but when I add this condition it returns True even if it's not changed...So I am concerned what to do in this case if I want to add condition like that?
It returns true if a column was updated. An update means that the query has SET the value of the column. Whether the previous value was the same as the new value is largely irelevant.
UPDATE table SET col = col
it's an update.
UPDATE table SET col = 99
when the col already had value 99 also it's an update.
Within the trigger, you have access to two internal tables that may help. The 'inserted' table includes the new version of each affected row, The 'deleted' table includes the original version of each row. You can compare the values in these tables to see if your field value was actually changed.
Here's a quick way to scan the rows to see if ANY column changed before deciding to run the contents of a trigger. This can be useful for example when you want to write a history record, but you don't want to do it if nothing really changed.
We use this all the time in ETL importing processes where we may re-import data but if nothing really changed in the source file we don't want to create a new history record.
CREATE TRIGGER [dbo].[TR_my_table_create_history]
ON [dbo].[my_table] FOR UPDATE AS
BEGIN
--
-- Insert the old data row if any column data changed
--
INSERT INTO [my_table_history]
SELECT d.*
FROM deleted d
INNER JOIN inserted i ON i.[id] = d.[id]
--
-- Use INTERSECT to see if anything REALLY changed
--
WHERE NOT EXISTS( SELECT i.* INTERSECT SELECT d.* )
END
Note that this particular trigger assumes that your source table (the one triggering the trigger) and the history table have identical column layouts.
What you do is check for different values in the inserted and deleted tables rather than use updated() (Don't forget to account for nulls). Or you could stop doing unneeded updates.
Trigger:
CREATE TRIGGER boo ON status2 FOR UPDATE AS
IF UPDATE (id)
BEGIN
SELECT 'DETECT';
END;
Usage:
UPDATE status2 SET name = 'K' WHERE name= 'T' --no action
UPDATE status2 SET name = 'T' ,id= 8 WHERE name= 'K' --detect
To shortcut the "No actual update" case, you need also check at the beginning whether your query affected any rows at all:
set nocount on; -- this must be the first statement!
if not exists (select 1 from inserted) and not exists (select 1 from deleted)
return;
SET NOCOUNT ON;
declare #countTemp int
select #countTemp = Count (*) from (
select City,PostCode,Street,CountryId,Address1 from Deleted
union
select City,PostCode,Street,CountryId,Address1 from Inserted
) tempTable
IF ( #countTemp > 1 )
Begin
-- Your Code goes Here
End
-- if any of these "City,PostCode,Street,CountryId,Address1" got updated then trigger
-- will work in " IF ( #countTemp > 1 ) " Code)
This worked for me
DECLARE #LongDescDirty bit = 0
Declare #old varchar(4000) = (SELECT LongDescription from deleted)
Declare #new varchar(4000) = (SELECT LongDescription from inserted)
if (#old <> #new)
BEGIN
SET #LongDescDirty = 1
END
Update table
Set LongDescUpdated = #LongDescUpdated
.....