How to delete duplicate rows in PostgreSQL using immediate table?

How to delete duplicate rows in PostgreSQL using immediate table?

In case you want to delete duplicate based on values of multiple columns, here is the query template: In this case, the statement will delete all rows with duplicate values in the column_1 and column_2 columns. To delete rows using an immediate table, you use the following steps:

How to delete a record in a PostgreSQL table?

The ctid field is a field that exists in every PostgreSQL table and is unique for each record in a table and denotes the location of the tuple. Below is a demonstration of using this ctid to delete records. Keep in mind only use the ctid if you have absolutely no other unique identifier to use.

How to delete duplicates over a set of columns?

A frequent question in IRC is how to delete rows that are duplicates over a set of columns, keeping only the one with the lowest ID. This query does that for all rows of tablename having the same column1, column2, and column3. Sometimes a timestamptz field is used instead of an ID field.

How to keep duplicate rows with lowest ID?

If you want to keep the duplicate rows with the lowest id, you use just need to flip the operator in the WHERE clause: To check whether the statement works correctly, let’s verify the data in the basket table: Perfect! the duplicate rows with the lowest ids are retained.

Is there way to find all duplicate records in PostgreSQL-stack?

The unique constraint is currently the first field called “id”, however I am now looking to add a constraint to make sure the year, user_id, sid and cid are all unique but I cannot apply the constraint because duplicate values already exist which violate this constraint. Is there a way to find all duplicates?

Is there way to delete CTEs from PostgreSQL?

Delete from or updating CTEs doesn’t work in Postgres, see the accepted answer of “PostgreSQL with-delete “relation does not exists””. Since you have no primary key you may (ab)use the ctid pseudo column to identify the rows to delete.

How to remove duplicate rows from a basket table?

Create a new table with the same structure as the one whose duplicate rows should be removed. Insert distinct rows from the source table to the immediate table. Drop the source table. Rename the immediate table to the name of the source table. The following illustrates the steps of removing duplicate rows from the basket table:

How to delete all duplicate rows except one in SQL Server?

In this post, I am sharing two different SQL scripts to delete the all duplicate rows except the one in SQL Server. Before a few days ago, I was working on a production report and found duplicates records in the few tables.