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How do I quickly rename a MySQL database (change schema name)?
The MySQL manual at MySQL covers this.
48 Answers
48
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how to exclude null values in array_agg like in string_agg using postgres?
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SQL Fiddle
select
id,
(select array_agg(a) from unnest(canonical_users) a where a is not null) canonical_users,
(select array_agg(a) from unnest(non_canonical_users) a where a is not null) non_canonical_users
fro...
How can I drop all the tables in a PostgreSQL database?
How can I drop all tables in PostgreSQL, working from the command line?
24 Answers
24
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I need to generate uuid for my rails application. What are the options(gems) I have? [duplicate]
... UUID has RFC! This will break any UUID validation (like in PostgreSQL)
– kixorz
Feb 10 '14 at 8:05
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updating table rows in postgres using subquery
...FROM (SELECT address_id, customer, address, partn
FROM /* big hairy SQL */ ...) AS subquery
WHERE dummy.address_id=subquery.address_id;
This syntax is not standard SQL, but it is much more convenient for this type of query than standard SQL. I believe Oracle (at least) accepts something sim...
How do I execute inserts and updates in an Alembic upgrade script?
...rent connection, and make a session with it.
Or use bind.execute() to use SQLAlchemy's lower level to write SQL queries directly. This is useful for simple migrations.
Use the models and session as you normally would in your application.
"""create teams table
Revision ID: 169ad57156f0
Revises...
CASCADE DELETE just once
I have a Postgresql database on which I want to do a few cascading deletes. However, the tables aren't set up with the ON DELETE CASCADE rule. Is there any way I can perform a delete and tell Postgresql to cascade it just this once? Something equivalent to
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Alter a MySQL column to be AUTO_INCREMENT
...ry key column AUTO_INCREMENT after the fact. I have tried the following SQL, but got a syntax error notification.
19 Ans...
Does PostgreSQL support “accent insensitive” collations?
In Microsoft SQL Server, it's possible to specify an "accent insensitive" collation (for a database, table or column), which means that it's possible for a query like
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What is the maximum length of a table name in Oracle?
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With standard SQL you can also determine the lengths by querying the table: select * from all_tab_columns where table_name = 'ALL_TAB_COLUMNS';
– JustinKSU
Mar 11 '16 at 23:18
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