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How to alter a column and change the default value?
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ALTER TABLE foobar_data MODIFY COLUMN col VARCHAR(255) NOT NULL DEFAULT '{}';
A second possibility which does the same (thanks to juergen_d):
ALTER TABLE foobar_data CHANGE COLUMN col col VARCHAR(255) NOT NULL DEFAULT '{}';
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How do I alter the position of a column in a PostgreSQL database table?
...ly defines column
order based on the attnum column of
the pg_attribute table. The only way
to change column order is either by
recreating the table, or by adding
columns and rotating data until you
reach the desired layout.
That's pretty weak, but in their defense, in standard SQL, the...
Unioning two tables with different number of columns
I have two tables (Table A and Table B).
5 Answers
5
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Fastest way to replace NAs in a large data.table
I have a large data.table , with many missing values scattered throughout its ~200k rows and 200 columns. I would like to re code those NA values to zeros as efficiently as possible.
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Select n random rows from SQL Server table
I've got a SQL Server table with about 50,000 rows in it. I want to select about 5,000 of those rows at random. I've thought of a complicated way, creating a temp table with a "random number" column, copying my table into that, looping through the temp table and updating each row with RAND() , and ...
How to import a single table in to mysql database using command line
...atabase using command line, but now my pain area is how to import a single table with its data to the existing database using command line.
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How do you determine what SQL Tables have an identity column programmatically
...umns in SQL Server 2005 that have identity columns and their corresponding table in T-SQL.
13 Answers
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Get size of all tables in database
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SELECT
t.NAME AS TableName,
s.Name AS SchemaName,
p.rows,
SUM(a.total_pages) * 8 AS TotalSpaceKB,
CAST(ROUND(((SUM(a.total_pages) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS TotalSpaceMB,
SUM(a.used_pages) * 8 AS UsedSpaceK...
mysql - how many columns is too many?
I'm setting up a table that might have upwards of 70 columns. I'm now thinking about splitting it up as some of the data in the columns won't be needed every time the table is accessed. Then again, if I do this I'm left with having to use joins.
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How to set initial value and auto increment in MySQL?
How do I set the initial value for an "id" column in a MySQL table that start from 1001?
10 Answers
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