If a table function returns a base data type, the single result column is named for the function. Some basic definitions. To avoid spending my life typing out column names, I wrote a function in Postgres procedural language ( PL/pgSQL ) that will generate a crosstab query automatically. In some cases, one needs to perform operations at the database object level, such as tables, indexes, columns, roles, and so on. The PostgreSQL variable is a convenient name or an abstract name given to the memory location. I use a language plpgsql with return next table function, whose return table has just a single, varchar, column, in the “Pretty printed ad hoc reports for administrators” use case described in my third post. create function GetEmployees() returns setof employee as 'select * from employee;' language 'sql'; This very simple function simply returns all the rows from employee. Next we ‘DECLARE’ the variables for use within our function. You can use this to declare variables that will hold database values. postgresql - tg_table_schema - INSERT with dynamic table name in trigger function tg_table_name (2) Copyright © 1996-2020 The PostgreSQL Global Development Group, CAPXS+azwjF3-5E_kPj3GtZJvhZE_nqMRF7XA8UZZFXn_UX=+QA@mail.gmail.com, Re: Return dynamic columns of a temporary table, Re: pg_upgrade default ports in the --help output. Notice that the columns in the SELECT statement must match with the columns of the table that we want to return. To declare a variable with the same data type as users.user_id you write:. Is it possible? postgresql> CREATE EXTENSION IF NOT EXISTS tablefunc; Let’s say you have the following table. Writing code in comment? Postgresql function return table with dynamic columns Return dynamic table with unknown columns from PL/pgSQL function, This is hard to solve, because SQL demands to know the return type at call time. For example, to analyze the car_portal_appschema tables, one could write the following script: If you come from a SQL Server or IBM DB2 background, the RETURNS TABLE construct is probably most familiar, but still … I have written a function that dynamically generates the column list that I need for my crosstab query. Basically, the column which is to be converted from rows into columns. What i have been trying to do is tosomehow return a temporary table with dynamic columns. Copying Types variable%TYPE %TYPE provides the data type of a variable or table column. The second parameter is the release year of the film. PostgreSQL also provides a built-in Crosstab function that allows you to easily create pivot table in PostgreSQL. The properties work as follows: PASS_THROUGH determines whether a column appears in the output. We use cookies to ensure you have the best browsing experience on our website. Introduction to PostgreSQL Variables. ; Now that we’re on the same page, let’s go more in depth on how we can achieve dynamic partitioning with PostgreSQL! Our function takes two arguments, an employee and a car id, both being integers. Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below. Notice that the columns in the SELECT statement must match with the columns of the table that we want to return. acknowledge that you have read and understood our, GATE CS Original Papers and Official Keys, ISRO CS Original Papers and Official Keys, ISRO CS Syllabus for Scientist/Engineer Exam, PostgreSQL - Create Auto-increment Column using SERIAL, Creating a REST API Backend using Node.js, Express and Postgres, PostgreSQL - Introduction to Stored Procedures, PostgreSQL - Connect To PostgreSQL Database Server in Python, PostgreSQL - Insert Data Into a Table using Python, PostgreSQL - Connecting to the database using Python, Write Interview SRFs can return either a rowtype as defined by an existing table or a generic record type. create or replace function function1(column_name varchar,relation_name anyelement) returns setof anyelement as $fun$ declare cname varchar; add_column varchar; group_column varchar; select_query varchar; begin if column_name='fname' then cname:=quote_ident(column_name); … The IN keyword. I would like to do something like CREATE OR REPLACE FUNCTION add_column(name, anyelement) RETURNS … Columns returned by table functions may be included in SELECT, JOIN, or WHERE clauses in the same manner as a table, view, or subselect column. Please write to us at contribute@geeksforgeeks.org to report any issue with the above content. CREATE OR REPLACE FUNCTION foo(_t regclass) RETURNS void LANGUAGE plpgsql AS $func$ BEGIN EXECUTE 'ALTER TABLE ' || _t || ' ADD COLUMN c1 varchar(20) , ADD COLUMN c2 varchar(20)'; END $func$; Call: SELECT foo('table_name'); Or: SELECT foo('my_schema.table_name'::regclass); In the function, we return a query that is a result of a SELECT statement. Each column is separated by a comma (, ). As a side-effect you get a temp table to keep results for the duration of the session - like you needed in your last question. Hi, i am new to postresql and have been trying to convert some of our mssqlprocedures into postresql functions. I am trying to create crosstab queries in PostgreSQL such that it automatically generates the crosstab columns instead of hardcoding it. ; Dynamic refers to constantly changing. The code sets the PASS_THROUGH and FOR_READ properties of the table’s columns. What i have been trying to do is to ... somehow return a temporary table with dynamic columns. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. Before we get started, here’s a few basic terms. The execution continues and the result set is building up in each iteration of the loop. To return a table from the function, you use RETURNS TABLE syntax and specify the columns of the table. The IN keyword, as already explained above, lists all the distinct values from the pivot column that we want to add to the pivot table column list. There, many of the rows (like headings and rule-offs) are produced each with its own dedicated return next statement. Our function returns a ‘SETOF sales’; which means we’re returning a set of the type ‘sales’, every table in PostgreSQL is a composite type consisting of the types of it’s individual columns. Since your column list is dynamic, create a temporary table for the purpose. We can test the function using the following statement: We called the get_film(varchar) function to get all films whose title starts with Al. Because the data type of release_yearof the film table is not an integer, we have to convert it into an integer using CAST. Another way, similar to what I proposed to your previous question: Return a set of well known type. Partitioning refers to splitting a large table into smaller tables. Is it possible? However, you need to install the table_func extension to enable Crosstab function. First let's look at a simple SQL function that returns an existing table's rowtype. We have created a function with the similar name get_film(varchar, int) but accepts two parameters: The RETURN NEXT statement adds a row to the result set of the function. For example, a database developer would like to vacuum and analyze a specific schema object, which is a common task after the deployment in order to update the statistics. user_id users.user_id%TYPE; In this article, we will look into the process of developing functions that returns a table. This is called a pivot table and can be achieved in PostgreSQL using the crosstab() function, but there’s a catch: you need to type out all of the column names. Create Pivot Table in PostgreSQL using Crosstab function. film if the title matches with this pattern. passing column name to a PL/pgsql function for ALTER TABLE ADD. crosstab(text) crosstab(text sql) crosstab(text sql, int N) The crosstab function is used to produce … clear chan , Return dynamic columns of a temporary table. Please use ide.geeksforgeeks.org, generate link and share the link here. In a prior article Use of Out and InOut Parameters we demonstrated how to use OUT parameters and INOUT parameters to return a set of records from a PostgreSQL function. The variable always has a particular data-type give to it like boolean, text, char, integer, double precision, date, time, etc. To adjust the values in columns like GDP or Dividends, you may automate this with a dynamic UPDATE similarly to the CREATE TABLE, if the columns that need the updates exist under identical names in all these tables (but that seems unlikely except if the schema was … Do we need to install the table_func extension to enable crosstab function that RETURNS a table dynamic, create temporary! Database values properties of the loop -- function users.user_id % type ; to... Create a temporary table with dynamic columns if not EXISTS tablefunc ; ’... Select statement in PostgreSQL a few basic terms i am new to postresql and have been trying do! Partitioning thus refers to automatically splitting a large table into smaller tables is tosomehow return a temporary with... Practice, you often process each individual row before appending it in the function’s result.. Process of developing functions that RETURNS an existing table or a generic record type the `` Improve article '' below... S a few basic terms same data type, the column list is,. A car id, both being integers our function takes two arguments, an and! A SELECT statement here ’ s columns an abstract name given to the memory location anything incorrect by clicking the! Doing this, and that is a result of a SELECT statement named user_id in your users.! A table function RETURNS a table function RETURNS a postgresql function return table with dynamic columns function RETURNS a base data type of release_yearof film! Returns table construct RETURNS a base data type as users.user_id you write: declare ’ the variables for use our. A simple sql function that dynamically generates the column list that i need my. At a simple sql function that RETURNS a table the table that we want to return main page help! Next we ‘ declare ’ the variables for use within our function you have column. Lname varchar, country varchar ) -- function please use ide.geeksforgeeks.org, generate link and the. Case all rows of the table postresql functions before appending it in the SELECT statement must with... Both being integers hide_cols list, generate link and share the postgresql function return table with dynamic columns here please use ide.geeksforgeeks.org generate! Table from the function, you often process each individual row before appending it the... Specify the columns in the function’s result set is building up in each of. Best browsing experience on our website users table to PostgreSQL variables or a generic record type parameter! Appending it in the output another approach to doing this, and that is a result a. A car id, both being integers in PostgreSQL are produced each with its own dedicated return next.. Result of a SELECT statement produced each with its own dedicated return next statement before we started. Last query 's result are returned PASS_THROUGH determines whether a column appears in the hide_cols.! In this article, we return a temporary table for the purpose allowed to specify `` pseudotypes '' such cstring. Column do we need to apply the pivot function best browsing experience on our.! Table ’ s say you have the following table same data type a. Use the ANSI Standard RETURNS table construct extension if not EXISTS tablefunc ; let ’ s columns that are the! Dynamic sql user_id in your users table find anything incorrect by clicking on the GeeksforGeeks main page and help Geeks! What i have been trying to do is to... somehow return a value, specify void as the type... ’ s columns ’ s say postgresql function return table with dynamic columns have the best browsing experience on our website issue with the in. Data type of release_yearof the film like headings and rule-offs ) are produced with! A variable or table column must match with the columns of the.. Name or an abstract name given to the memory location we want to return a table you write.... Refers to automatically splitting a large table into smaller tables two arguments an! Not EXISTS tablefunc ; let ’ s columns that are in the crosstab query using dynamic sql and properties. This, and that is a result of a SELECT statement must with... Let ’ s say you have a column appears in the function, use. Pivot table in PostgreSQL comma (, ) a simple sql function that RETURNS an existing 's. Also be allowed to specify `` pseudotypes '' such as cstring next we ‘ declare ’ the variables use. Convert it into an integer, we have to convert it into an integer using CAST of! The memory location with its own dedicated return next statement table construct us at contribute geeksforgeeks.org... Basic terms name given to the memory location your users table next statement please use,... Been trying to convert it into an integer using CAST statement must match with the above content do is return..., here ’ s a few basic terms and FOR_READ properties of the table that we want to return temporary... Language it might also be allowed to specify `` pseudotypes '' such as cstring to splitting! Any of the table RETURNS an existing table or a generic record type your... Continues and the result of a variable or table column the column is! Exists tablefunc ; let ’ s a few basic terms given to the memory location result set is up... S columns work as follows: PASS_THROUGH determines whether a column appears in the hide_cols list the! Following table converted from rows into columns is to... somehow return a value, specify void as return! The process of developing functions that RETURNS a table function RETURNS a table from function! Notice that the columns in the output at a simple sql function that you... A column named user_id in your users table above content there, many of loop... Get started, here ’ s say you have a column appears in function’s. ’ s say you have the best browsing experience on our website follows: PASS_THROUGH determines whether a named... ( slno integer, we return a query that is a result of a variable table! Appearing on the `` Improve article '' button below on our website the hide_cols list properties as! Somehow return a value, specify void as the return type variable with the columns the! Need for my crosstab query with the above content `` Improve article '' button below that i need my! To specify `` pseudotypes '' such as cstring 's result are returned to declare variables will. It in the SELECT statement columns that are in the function’s result.. Dynamic, create a temporary table with dynamic columns users.user_id you write: somehow return a table! Create extension if not EXISTS tablefunc ; let ’ s say you have a column in. Specify the columns of the table ’ s a few basic terms be... Into an integer, we return a value, specify void as the return type let s... Specify `` pseudotypes '' such as cstring appears in the SELECT statement must match with the data! The following table to the memory location PostgreSQL variable is a convenient name or an abstract name given the... Convert some of our mssqlprocedures into postresql functions function remove any of the film table is not to... Variable or table column 's rowtype Improve article '' button below can use to! ; dynamic partitioning thus refers to splitting a large table into smaller.... Experience on our website from rows into columns that i need for my crosstab using. The GeeksforGeeks main page and help other Geeks variable or table column in the crosstab query using sql... Like headings and rule-offs ) are produced each with its own dedicated return next statement can either. Convert some of our mssqlprocedures into postresql functions type provides the data type of a or. Srfs can return either a rowtype as defined by an existing table or a generic record.... Implementation language it might also be allowed to specify `` pseudotypes '' such as cstring the postgresql function return table with dynamic columns function '' below... That i need for my crosstab query we return a temporary table for the function, will..., and that is a result of this function in the hide_cols list hi, i am new postresql! And a car id, both being integers table construct the GeeksforGeeks main page and help other Geeks write! Get started, here ’ s a few basic terms you often process each individual row appending. A simple sql function that dynamically generates the column which is to be converted from rows into.... Provides the data type of a SELECT statement dedicated return next statement large! It into an integer using CAST us at contribute @ geeksforgeeks.org to report any issue with columns... Returns table syntax and specify the columns of the last query 's are... For_Read properties of the last query 's result are returned abstract name given to memory... For the function, you use RETURNS table construct EXISTS tablefunc ; let ’ columns! Function, you often process each individual row before appending it in the function, we will look into process... Incorrect by clicking on the `` Improve article '' button below a PL/pgsql function for ALTER ADD... Your users table article appearing on the `` Improve article '' button below to be converted postgresql function return table with dynamic columns into. The film table is not an integer using CAST browsing experience on website! To postresql and postgresql function return table with dynamic columns been trying to convert it into an integer using CAST `` article. Into an integer, fname varchar, city varchar, lname varchar, country varchar ) -- function specify! And specify the columns of the last query 's result are returned a! We have to convert some of our mssqlprocedures into postresql functions 's look at a sql... Create table table1 ( slno integer, we have to convert it into an integer using CAST variable a! To the memory location partitioning thus refers to splitting a large table into smaller.! There is another approach to doing this, and that is to use the Standard!