Is this the right way to do it? This is the first time I am doing something with a temp table. The SELECT INTO statement can create a temporary table from two or more tables. INSERT into product_temp_mapping (accountid, productUID, sampleproductId) Hint: If you want to discard the results of a SELECT, use PERFORM instead.ĬREATE TEMP TABLE IF NOT EXISTS product_temp_mappingįOREACH sampleproductId IN ARRAY productIds When I try to get the data back from the table I get an error: ERROR: query has no destination for result data For that reason, it's generally not a good idea to use them anywhere except when you understand the costs and you know it to provide a performance improvement.I am creating a temp table, and am fetching data from multiple tables and inserting data into it. In PostgreSQL, the SELECT INTO statement creates a new table, copies data from the original table, and pastes it into the newly created table. CREATE TEMP TABLE lookup(key, value) ASĪ CTE in PostgreSQL forces materialization. Assuming this is for SQL Server : the CTE is good for only one statement - so you cannot have both a SELECT and an INSERT - just use the INSERT: WITH cOldest AS ( SELECT, ROWNUMBER () OVER (PARTITION BY MyKey ORDER BY SomeColumn DESC) AS rnDOB FROM MyTable ) INSERT INTO MyTempTable (Col1, Col2. If you must write a select statement you can do that too (and you don't need a CTE).
While many answers here are suggesting using a CTE, that's not preferable. Unlike the SELECT statement, the SELECT INTO statement does not return data to the client. The new table columns have names and data types linked with the output columns of the SELECT clause.
Which yields: key |val |color |lookup_key |įirst always use the standardized CREATE TABLE AS, SELECT INTO as suggested in other answers has been a deprecated syntax for over a decade. In PostgreSQL, the SELECT INTO statement allows users to create a new table and inserts data returned by a query. Or JOIN the values with another relationship (which again can be a regular table, view, etc.), e.g.: SELECT * Then you can get a Cartesian product with a CROSS JOIN (where the other relationship can be, of course, a regular table, view, etc.). In SQL Server you can use a SELECT INTO statement to create a temporary table based on the query results. You can inline them: SELECT *įROM (VALUES(0::INT, -99999::NUMERIC), (1, 100)) AS lookup(key, val) You really don't need to create a table nor use a CTE, if all you need is to use a few values in your queries. The data is not returned to the client, as it is with a normal SELECT. There are, however, many instances where the optimization fence can actually enhance performance, so this is something to be aware of, not to blindly avoid. SELECT INTO creates a new table and fills it with data computed by a query.
POSTGRESQL SELECT INTO TEMP TABLE HOW TO
The following query filters the rows in which the Name column starts with the F character and then inserts the resultsets into the temporary table. How to insert values into a table from a select query in PostgreSQL Ask Question. The query syntax to create a temporary table is as the following. There are many good reasons for using CTEs, but there can be quite a significant performance hit, if not used carefully. At the same time, we can filter some rows of the Location and then insert the result set into a temporary table. Syntax to create PostgreSQL Temporary tables. Note, also from the comments by a_horse_with_no_name, and in the OP's original question, this includes a cast to the correct datatypes inside the values list and uses a CTE (WITH) statement.Īlso, as pointed out in Evan Carrol's answer, in Postgres prior to version 12 a CTE query is always an optimization fence, ie, the CTE is always materialized. Therefore, while the above examples are valid for plain SQL, the CREATE TABLE form should be preferred. , but that the former is a superset of the latter and that SELECT INTO is used in plpgslq for assigning a value to a temporary variable - so it would fail in that case. SELECT * INTO temporary table temp_table FROM vals ĮDIT: As pointed out by a_horse_with_no_name, in the docs it states that CREATE TABLE AS.
To actually create a temporary table in a similar fashion, use: WITH vals (k,v) AS (VALUES (0,-9999), (1, 100)) If you just want to select from some values, rather than just creating a table and inserting into it, you can do something like: WITH vals (k,v) AS (VALUES (0,-9999), (1, 100)) EDIT: I am leaving the original accepted answer as it is, but please note that the edit below, as suggested by a_horse_with_no_name, is the preferred method for creating a temporary table using VALUES. create temporary table scratchusers (id - Or create a temporary table based on the output of a select create temp table activeusers as select.
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