Do you need the same table structure as an existing table in your database, but empty of rows? Oracle SQL’s CREATE TABLE AS statement achieves this easily. Continue reading and learn how with a simple example…
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I have this FRIENDS table that I want to duplicate:
However, the FRIENDS table has 7 rows of data and I want the clone table to be empty.
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CREATE TABLE AS
Using SELECT * – or explicitly listing the individual columns you need – in a CREATE TABLE AS command with a WHERE clause predicate that evaluates to FALSE, creates a table based on the FROM clause table of the SELECT statement, but will not fill it with rows:
(SELECT * FROM FRIENDS
WHERE 1 = 2);
Viewing the newly created SAME_FRIENDS table description, we can see it has the same structure as the FRIENDS table it is based on:
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Querying the SAME_FRIENDS table shows there are no rows present in the table:
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This is a quick and simple way you can essentially duplicate a table’s exact structure, without populating it with any rows.
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Josh Otwell has a passion to study and grow as a SQL Developer and blogger. Other favorite activities find him with his nose buried in a good book, article, or the Linux command line. Among those, he shares a love of tabletop RPG games, reading fantasy novels, and spending time with his wife and two daughters.
Disclaimer: The examples presented in this post are hypothetical ideas of how to achieve similar types of results. They are not the utmost best solution(s). The majority, if not all, of the examples provided, are performed on a personal development/learning workstation environment and should not be considered production quality or ready. Your particular goals and needs may vary. Use those practices that best benefit your needs and goals. Opinions are my own.