How do I update a column value (varchar(20), not null) with a "blank" value?
If you want to update it with NULL you will need to change it to allow NULL. Otherwise update with an empty string "".
Update TableName Set ColumnName='' where [Condtion] // To update column with an enpty values
If there have any int column which you may want to do null
Update TABLE_NAME set name = '',id = cast(NULLIF(id,'') as NVARCHAR)
Related
Is it possible to copy data from column A to column B for all records in a table in SQL?
How about this
UPDATE table SET columnB = columnA;
This will update every row.
UPDATE table_name SET
destination_column_name=orig_column_name
WHERE condition_if_necessary
This will update all the rows in that columns if safe mode is not enabled.
UPDATE table SET columnB = columnA;
If safe mode is enabled then you will need to use a where clause.
I use primary key as greater than 0 basically all will be updated
UPDATE table SET columnB = columnA where table.column>0;
If you want to copy a column to another column with a different data type in PostgresSQL, you must cast/convert to the data type first, otherwise it will return
Query 1 ERROR: ERROR: column "test_date" is of type timestamp without
time zone but expression is of type character varying LINE 1: update
table_name set test_date = date_string_col
^ HINT: You will need to rewrite or cast the expression.
An example of converting varchar to timestamp:
update table_name set timestamp_col = date_string_col::TIMESTAMP;
An example of converting varchar to int:
update table_name set int_column = string_col::INTEGER;
but any column type(except file or the similar) can be copied to string(character varying) without cast the type.
I have a table with nullable column.
create table testgt(retrycount number(3));
I have to update for the following cases.
If the value is null I should update as 0
and if the value is not null I should increment by 1.
Can a single query handle this?
You can use coalesce():
update testgr
set retrycount = coalesce(retrycount + 1, 0);
If I need to replace all mentions of "TOTA" in a column with nothing would I use the following concept? It seems simple but all the tutorials that I find are not in plain enough English for someone who picked up SQL last week.
Update Tablename
set indcode =case when indcode in('TOTA', then 'blank' else 'leave it alone' End);
You should set to null for assign blank value
Update Tablename
set indcode = NULL
where indcode ='TOTA';
and use where for filter the row to update
if you need a set of value for filter you can use a IN clause eg
Update Tablename
set indcode = NULL
where indcode in ('TOTA', '0', '000000');
or for complex case you can use case when ..
Update Tablename
set indcode = case when 'TOTA' then NULL
when '0' then '000000'
else indcode
END
You were missing a equal sign and a closing parentheses, and as written you would have updated it to the string blank, not an empty string, and finally, you need to decide if you want it to be updated to an empty (zero-length) string, or to the built-in database value called null, which represents, in all relational databases, that the value is not known or is unspecified (as opposed to explicitly being an empty or zero-length string.)
To update to an empty (zero-Length) string, write'
Update Tablename
set indcode = case when indcode = 'TOTA' then ''
else indcode end;
but you really don't need to update the ones to be left alone, so just add a filter (a Where clause) with that predicate expression
Update Tablename
set indcode = ''
Where indcode = 'TOTA'
If you really want to update it to Null, and not to an empty string, then first check and make sure that the column indCode is set to allow nulls, and write:
Update Tablename
set indcode = Null
Where indcode = 'TOTA'
Is it possible to set NULL value for int column in update statement?
How can I write the update statement in this case?
Assuming the column is set to support NULL as a value:
UPDATE YOUR_TABLE
SET column = NULL
Be aware of the database NULL handling - by default in SQL Server, NULL is an INT. So if the column is a different data type you need to CAST/CONVERT NULL to the proper data type:
UPDATE YOUR_TABLE
SET column = CAST(NULL AS DATETIME)
...assuming column is a DATETIME data type in the example above.
By using NULL without any quotes.
UPDATE `tablename` SET `fieldName` = NULL;
Provided that your int column is nullable, you may write:
UPDATE dbo.TableName
SET TableName.IntColumn = NULL
WHERE <condition>
If this is nullable int field then yes.
update TableName
set FiledName = null
where Id = SomeId
How do I clear the value from a cell and make it NULL?
I think Zack properly answered the question but just to cover all the bases:
Update myTable set MyColumn = NULL
This would set the entire column to null as the Question Title asks.
To set a specific row on a specific column to null use:
Update myTable set MyColumn = NULL where Field = Condition.
This would set a specific cell to null as the inner question asks.
If you've opened a table and you want to clear an existing value to NULL, click on the value, and press Ctrl+0.
If you are using the table interface you can type in NULL (all caps)
otherwise you can run an update statement where you could:
Update table set ColumnName = NULL where [Filter for record here]
Use This:
Update Table Set Column = CAST(NULL As Column Type) where Condition
Like This:
Update News Set Title = CAST(NULL As nvarchar(100)) Where ID = 50
Ctrl+0 or empty the value and hit enter.
Just as a little extension to Jeff Martin's and Zack Peterson's solution.
If you still want to set several values from the columns to null you can simply set the query to
UPDATE myTable SET MyColumn1 = NULL, MyColumn2 = NULL, MyColumn3 = NULL, ...
CTRL+0 doesn't seem to work when connected to an Azure DB.
However, to create an empty string, you can always just hit 'anykey then delete' inside a cell.