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How to use a CTE in a PostgreSQL statement?
In this syntax: 1 First, specify the name of the CTE following by an optional column list. 2 Second, inside the body of the WITH clause, specify a query that returns a result set. 3 Third, use the CTE like a table or view in the statement which can be a SELECT, INSERT, UPDATE, or DELETE.
How to insert data into PostgreSQL common table expression?
Illustrate the result of the above INSERT INTO statement by using the following SQL statement and snapshot. Now, we will insert some data into the student’ table by using the PostgreSQL INSERT INTO statement as follows: Illustrate the result of the above INSERT INTO statement by using the following SQL statement and snapshot.
How to use CTE with a DELETE statement?
Another, CTE with a DELETE statement. Reusing the same CTE query definition. Later, joining CTE result with #SysObjects table and deleting rows having object_ids as odd numbers. Querying SELECT * FROM #SysObjects shows rows have been deleted.
Can a CTE be inserted into a SELECT statement?
In the following query, using CTE, named SysObjectsCTE. This CTE includes a SELECT statement in query definition and referring to metadata table with column names specified. Furthermore, the result of CTE inserted into #SysObjects temp table. As a rule, we can not have any other statement in between the declaration of CTE and the use of CTE.
When to use return value of insert in PostgreSQL?
If you want to be really paranoid (a good thing, they really are you to get you after all), then you could use currval () but you’d need to know the name of the relevant sequence:
How to find lastval of insert in PostgreSQL?
The automatically generated sequence is usually named t_c_seq where t is the table name and c is the column name but you can always find out by going into psql and saying: FYI: lastval () is, more or less, the PostgreSQL version of MySQL’s LAST_INSERT_ID.
How to join a CTE to a table?
In the following example, we will use the rental and staff tables: The following statement illustrates how to join a CTE with a table: First, the CTE returns a result set that includes staff id and the number of rentals. Then, join the staff table with the CTE using the staff_id column.