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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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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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Inserting multiple rows in mysql
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it's also possible to use INSERT INTO Table SELECT 1, '14/05/2012', 3 UNION SELECT 2, '05/14/2012', 3. of course, this will only be better of the inserted values are coming from different tables.
– Zohar Peled
Jun 1 '15 at 9...
Sort rows in data.table in decreasing order on string key `order(-x,v)` gives error on data.table 1.
Let's say I have the following data.table in R :
3 Answers
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How do I create a foreign key in SQL Server?
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create table question_bank
(
question_id uniqueidentifier primary key,
question_exam_id uniqueidentifier not null,
question_text varchar(1024) not null,
question_point_value decimal,
constraint fk_questionbank_ex...
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 can foreign key constraints be temporarily disabled using T-SQL?
... database just run this code:
-- disable all constraints
EXEC sp_MSforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"
To switch them back on, run: (the print is optional of course and it is just listing the tables)
-- enable all constraints
exec sp_MSforeachtable @command1="print '?'", @command...
Rails migration for change column
We have script/generate migration add_fieldname_to_tablename fieldname:datatype syntax for adding new columns to a model.
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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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How to make a JTable non-editable
How to make a JTable non-editable? I don't want my users to be able to edit the values in cells by double-clicking them.
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