Mysql – How to get MySQL to use the value returned by a function as a default

default valueMySQLmysql-5phpmyadmin

I have a pre-existing table that has a column to that can hold a UUID.

I'd like to be able to define a default such that new rows coming in (from legacy systems) will still get a UUID defined, via the UUID() function — is it possible to configure the default of a column to be a value returned by UUID (in a similar manner to how you can for the UNIX_TIMESTAMP() in phpMyAdmin)

Best Answer

Using a trigger

You can't use functions as defaults in MySQL, except for CURRENT_TIMESTAMP for TIMESTAMP columns

Related Solutions

Postgresql – How to use a default value in a Select query in PostgreSQL

SELECT coalesce(MAX(post_id),0) AS max_id FROM my_table WHERE org_id = 3

SELECT case count(*) when 0 then 0 else MAX(post_id) end AS max_id
FROM my_table 
WHERE org_id = 3;

if you want max(post_id) to be null when there is 1 row but post_id is null

_dbfiddle

Mysql – use the “import” tool on PHPMyAdmin multiple times

Yes this is possible, although you need to watch out for the following:

a) Export using extended inserts so that the extended SQL syntax is used which will reduce the size of your SQL files (If you are exporting using PHPMyAdmin select both complete and extended insert options, as it creates complete inserts with extended insert syntax for large tables)

b) Try using the GZip format which will compress the SQL files and make them smaller (depending on the hosting provider setup this may be an issue so you need to test it out with a small table)

c) Export the tables in such an order that tables with foreign keys are imported last

Best Answer

Related Solutions

Postgresql – How to use a default value in a Select query in PostgreSQL

Mysql – use the “import” tool on PHPMyAdmin multiple times

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