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Adding a new SQL column with a default value
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Try this:
ALTER TABLE table1 ADD COLUMN foo INT DEFAULT 0;
From the documentation that you linked to:
ALTER [ONLINE | OFFLINE] [IGNORE] TABLE tbl_name
alter_specification [, alter_specification] ...
alter_specification:
...
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What is the difference between “INNER JOIN” and “OUTER JOIN”?
... the outer parts of a Venn diagram union.
Examples
Suppose you have two tables, with a single column each, and data as follows:
A B
- -
1 3
2 4
3 5
4 6
Note that (1,2) are unique to A, (3,4) are common, and (5,6) are unique to B.
Inner join
An inner join using either of the...
HTML table with fixed headers?
Is there a cross-browser CSS/JavaScript technique to display a long HTML table such that the column headers stay fixed on-screen and do not scroll with the table body. Think of the "freeze panes" effect in Microsoft Excel.
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Multiple select statements in Single query
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SELECT (
SELECT COUNT(*)
FROM user_table
) AS tot_user,
(
SELECT COUNT(*)
FROM cat_table
) AS tot_cat,
(
SELECT COUNT(*)
FROM course_table
) AS tot_course
share
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Difference between one-to-many and many-to-one relationship
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From this page about Database Terminology
Most relations between tables are one-to-many.
Example:
One area can be the habitat of many readers.
One reader can have many subscriptions.
One newspaper can have many subscriptions.
A Many to One relation is the same as o...
Postgresql - change the size of a varchar column to lower length
I have a question about the ALTER TABLE command on a really large table (almost 30 millions rows).
One of its columns is a varchar(255) and I would like to resize it to a varchar(40) .
Basically, I would like to change my column by running the following command:
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How do you copy a record in a SQL table but swap out the unique id of the new row?
...es close to what I need, but my scenario is slightly different. The source table and destination table are the same and the primary key is a uniqueidentifier (guid). When I try this:
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How to find foreign key dependencies in SQL Server?
... all Foreign Key Relationships within the current database.
SELECT
FK_Table = FK.TABLE_NAME,
FK_Column = CU.COLUMN_NAME,
PK_Table = PK.TABLE_NAME,
PK_Column = PT.COLUMN_NAME,
Constraint_Name = C.CONSTRAINT_NAME
FROM
INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS C
INNER JOIN INF...
How to get the mysql table columns data type?
I want to get the column data type of a mysql table.
11 Answers
11
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Convert Rows to columns using 'Pivot' in SQL Server
I have read the stuff on MS pivot tables and I am still having problems getting this correct.
8 Answers
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