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Displaying posts with tag: dynamic sql (reset)
SQL from SQL

This is a simple technique, to write a report that generates SQL syntax, that you can then turn around and execute. I've heard this called "SQL from SQL" or sometimes "dynamic SQL"--although it doesn't use prepared statements or anything like that.

There are a few simple options in SQL*Plus (Oracle's command-line tool) to accomplish this, and a few simple--but different--options in mysql (MySQL's command-line tool).

Try this line:

shell> mysql --silent --skip-column-names -e "select concat('describe ', table_name, ';') from information_schema.tables where table_schema = 'world'"

(Note I'm supplying my username and password to the session from an option file.) This sends the following to standard output:

describe City;
describe Country;
describe CountryLanguage;

The trick is to select the data you want from your system, combined with the …

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Using Events to manage a Table Partitioned by Date: part 2

Thanks all for the help on getting my log_addpartition event running, dynamic SQL was just the ticket. 

I'm now focusing on writing the sister event: 'log_removepartition', which will find and purge partitions older than some time interval. The information schema comes in quite handy here, as I can query the PARTITIONS table to see all partitions.

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