Postgres cursor without function

Once a cursor has been opene it can be manipulated with the statements described here. These manipulations need not occur in the same function that opened the cursor to begin with. You can return a refcursor value out of a function and let the caller operate on the cursor. The following get_film_titles(integer) function accepts an argument that represents the release year of a film.

Inside the function, we query all films whose release year equals to the released year passed to the function. With SQL Server, I can execute code ad hoc T-SQL code with full procedural logic through SQL Server Management Studio, or any other client. I want to make a Function in postgreSQL that reads the result of a query with a cursor and returns the result in a table.

I am not very familiar with cursors but I have make an effort with no result. If you define a cursor without parameters, the query will always return the same result set, unless influenced by external data. A cursor parameter can be used anywhere that a value-yielding expression can be used. Postgresql cant declare cursor.

Hot Network Questions What does boys rule, girls drool mean? As far as I know PostGres does not support multiple result sets without cursors like SQL Server does. Basically you could join the result sets for example using UNION ALL operation but that would require that the structure and the data types of both sets are the same.

Based on your question, this is not the case. The IF statement is used to execute a command conditionally. If the condition evaluates to false. Because the result of SQL statement is directly handed over as the result of function , clause INTO is not used. No variables are filled by the result yet.

Named cursor has sence only for updatable cursors. This variable will be used to store the rows coming from the query in the main body of the function. The main body does a loop over the group by query stated setting r to each row in sequence.

The structure of those two tables is not same. I need to return only these two select statements from function. Provided by: postgres -xc-client_1.

After the cursor is create rows are fetched from it using FETCH(7). How can I keep a result set without keeping the transaction open? Ask Question Asked years, months ago. Thus, DECLARE without WITH HOLD is useless outside.

One workaround for such cases is to declare the cursor WITH HOLD and commit the transaction. This function is invoked in the following anonymous block by assigning the function’s return value to a cursor variable declared in the anonymous block’s declaration section. The result set is fetched using this cursor variable and then it is closed. And now for something a bit more complex.

Let us first agree on terminology. A procedure is merely a function returning void. This is a big title which already brought a lot of discussions over decades. In any case, they execute queries like prepared statements , so you should be aware that the cursor slowness. Cursor without parameters (simplest) Declaring a cursor without any parameters is the simplest cursor.

For example, you could define a cursor called cas below. This set of commands is taken from the psql command-line tool. A more interesting usage is to return a reference to a cursor that a function has create allowing the caller to read the rows.

This provides an efficient way to return large row sets from functions. How to return multi result set from function ?