How to Efficiently Create Temporary Tables in PostgreSQL?

Creating Temporary Tables in SQL

When attempting to create a temporary table selecting data based on a specific register type, users may encounter errors. To resolve this, understanding the correct syntax and its limitations is crucial.

In PostgreSQL, temporary tables can be created using the CREATE TEMP TABLE AS syntax:

CREATE TEMP TABLE temp1 AS
SELECT dataid
     , register_type
     , timestamp_localtime
     , read_value_avg
FROM   rawdata.egauge
WHERE  register_type LIKE '%gen%'
ORDER  BY dataid, timestamp_localtime;

Temporary tables act as static snapshots of the data and reside in RAM if the temp_buffers setting allows. They are session-specific and vanish at its end, unless created with ON COMMIT DROP, which deletes them at the end of the transaction.

Alternatively, temporary tables can be created dynamically using CREATE VIEW. However, their behavior and usage differ significantly from static temporary tables.

While the SQL standard includes SELECT INTO for creating temporary tables, its use is discouraged in favor of CREATE TABLE AS. Additionally, CREATE TABLE LIKE (...) only copies the table structure and no data, while derived tables in CTEs or subqueries offer less overhead for temporary data use within a single query.

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