Postgres cte update. The WITH clause defines a CTE named Updated_Customers.
Postgres cte update. Let’s explore some real-world PostgreSQL CTE examples to understand their functionality and use cases. Which technique is more appropriate depends on the specific circumstances. For examples below, we will be using the sample database (ie, dvdrental). There are two ways to modify a table using information contained in other tables in the database: using sub-selects, or specifying additional tables in the FROM clause. Trying to update the same row twice in a single statement is not supported. Jul 16, 2024 · Explore the essentials of Common Table Expressions (CTE) in PostgreSQL and learn practical tips on effectively using CTEs to simplify complex queries. Please note that sometimes it's worth trying it with a CTE, as explained in the answer below by simPod. The UPDATE statement then modifies the city column in the customers table based on the new_city values calculated in the CTE. But sure, using REPEATABLE READ and not using FOR UPDATE would also solve the problem. On some (big) tables, using one over the other can yield great performance benefits. This CTE selects customer data and creates a new new_city column, updating 'Old City' to 'New City'. Only one of the modifications takes place, but it is not easy (and sometimes not possible) to reliably predict which one. Mar 14, 2022 · FOR UPDATE would lock the rows, so that there can be no concurrent modifications and consequently no serialization errors. . The WITH clause defines a CTE named Updated_Customers. Jul 15, 2025 · Usage: Finally, use the CTE like a table or view in the statement, which can be a SELECT, INSERT, UPDATE, or DELETE. dbabt efdch pvjqd wryde oyaxh zfnkh pryk lzbandl etozzr qctvtbu