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Best practices for SQL varchar column length [closed]
Every time is set up a new SQL table or add a new varchar column to an existing table, I am wondering one thing: what is the best value for the length .
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Alter a MySQL column to be AUTO_INCREMENT
I’m trying to modify a table to make its primary key column AUTO_INCREMENT after the fact. I have tried the following SQL, but got a syntax error notification.
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How to 'insert if not exists' in MySQL?
I started by googling, and found this article which talks about mutex tables.
10 Answers
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How to see the values of a table variable at debug time in T-SQL?
Can we see the values (rows and cells) in a table valued variable in SQL Server Management Studio (SSMS) during debug time? If yes, how?
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How To Create Table with Identity Column
I have an existing table that I am about to blow away because I did not create it with the ID column set to be the table's Identity column.
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With MySQL, how can I generate a column containing the record index in a table?
...itialization without requiring a separate SET command.
Test case:
CREATE TABLE league_girl (position int, username varchar(10), score int);
INSERT INTO league_girl VALUES (1, 'a', 10);
INSERT INTO league_girl VALUES (2, 'b', 25);
INSERT INTO league_girl VALUES (3, 'c', 75);
INSERT INTO league_girl...
How do I explicitly specify a Model's table-name mapping in Rails?
I have a Model class called Countries and I want it to map to a DB table called 'cc'.
2 Answers
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MySQL select 10 random rows from 600K rows fast
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SELECT column FROM table
ORDER BY RAND()
LIMIT 10
Not the efficient solution but works
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MySQL query to get column names?
I'd like to get all of a mysql table's col names into an array in php?
21 Answers
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How do SQL EXISTS statements work?
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For 'each' row from Suppliers, check if there 'exists' a row in the Order table that meets the condition Suppliers.supplier_id (this comes from Outer query current 'row') = Orders.supplier_id. When you find the first matching row, stop right there - the WHERE EXISTS has been satisfied.
The magic ...