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INNER JOIN vs LEFT JOIN performance in SQL Server
I've created SQL command that uses INNER JOIN on 9 tables, anyway this command takes a very long time (more than five minutes). So my folk suggested me to change INNER JOIN to LEFT JOIN because the performance of LEFT JOIN is better, despite what I know. After I changed it, the speed of query got si...
SQL keys, MUL vs PRI vs UNI
...hat the field is (part of) a non-unique index. You can issue
show create table <table>;
To see more information about the table structure.
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jQuery DataTables: control table width
I have a problem controlling the width of a table using the jQuery DataTables plugin. The table is supposed to be 100% of the container width, but ends up being an arbitrary width, rather less than the container width.
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Bootstrap table striped: How do I change the stripe background colour?
With Bootstrap class table-striped , every other row in my table has a background colour equal to #F9F9F9 . How can I change this colour?
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Check for changes to an SQL Server table?
How can I monitor an SQL Server database for changes to a table without using triggers or modifying the structure of the database in any way? My preferred programming environment is .NET and C#.
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How to version control a record in a database
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Let's say you have a FOO table that admins and users can update. Most of the time you can write queries against the FOO table. Happy days.
Then, I would create a FOO_HISTORY table. This has all the columns of the FOO table. The primary key is th...
Delete all records in a table of MYSQL in phpMyAdmin
I use wampserver 2.2. When I want to delete all records of a table in phpMyAdmin (select all) it deletes only one record not all records. Why it does not delete all records?
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How to set auto increment primary key in PostgreSQL?
I have a table in PostgreSQL with 22 columns, and I want to add an auto increment primary key.
7 Answers
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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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Create an index on a huge MySQL production table without table locking
I need to create an index on a ~5M rows MySQL table. It is a production table, and I fear a complete block of everything if I run a CREATE INDEX statement...
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