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How to update column with null value
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No special syntax:
CREATE TABLE your_table (some_id int, your_column varchar(100));
INSERT INTO your_table VALUES (1, 'Hello');
UPDATE your_table
SET your_column = NULL
WHERE some_id = 1;
SELECT * FROM your_table WHERE your_column IS NULL;
+---...
Simple way to copy or clone a DataRow?
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You can use ImportRow method to copy Row from DataTable to DataTable with the same schema:
var row = SourceTable.Rows[RowNum];
DestinationTable.ImportRow(row);
Update:
With your new Edit, I believe:
var desRow = dataTable.NewRow();
var sourceRow = dataTable.Rows[rowNum]...
How do I modify a MySQL column to allow NULL?
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You want the following:
ALTER TABLE mytable MODIFY mycolumn VARCHAR(255);
Columns are nullable by default. As long as the column is not declared UNIQUE or NOT NULL, there shouldn't be any problems.
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Android: upgrading DB version and adding new table
I've already created sqlite tables for my app, but now I want to add a new table to the database.
5 Answers
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How to Use slideDown (or show) function on a table row?
I'm trying to add a row to a table and have that row slide into view, however the slidedown function seems to be adding a display:block style to the table row which messes up the layout.
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Can you create nested WITH clauses for Common Table Expressions?
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While not strictly nested, you can use common table expressions to reuse previous queries in subsequent ones.
To do this, the form of the statement you are looking for would be
WITH x AS
(
SELECT * FROM MyTable
),
y AS
(
SELECT * FROM x
)
SELECT * FROM y
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Most common way of writing a HTML table with vertical headers?
... option isn't quite valid HTML in the sense that all of the rows (TR) in a table should contain an equal number of columns (TD). Your header has 1 while the body has 3. You should use the colspan attribute to fix that.
Reference: "The THEAD, TFOOT, and TBODY sections must contain the same number of...
Convert a list of data frames into one data frame
... but in about Sep 2011 a new function rbindlist was introduced in the data.table package version 1.8.2, with a remark that "This does the same as do.call("rbind",l), but much faster". How much faster?
library(rbenchmark)
benchmark(
do.call = do.call("rbind", listOfDataFrames),
plyr_rbind.fill ...
How to avoid mysql 'Deadlock found when trying to get lock; try restarting transaction'
I have a innoDB table which records online users. It gets updated on every page refresh by a user to keep track of which pages they are on and their last access date to the site. I then have a cron that runs every 15 minutes to DELETE old records.
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HTML input textbox with a width of 100% overflows table cells
Does anyone know why the input elements with a width of 100% go over the table's cells border.
14 Answers
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