![]() ![]() The following illustrates the syntax of the cursor FOR LOOP statement: FOR record IN cursor_nameĬode language: SQL (Structured Query Language) ( sql ) The cursor is also closed if a statement inside the loop transfers control outside the loop, e.g., EXIT and GOTO, or raises an exception. If there is no row to fetch, the cursor FOR LOOP closes the cursor. In each loop iteration, the cursor FOR LOOP statement fetches a row from the result set into its loop index. ![]() The cursor FOR LOOP implicitly creates its loop index as a record variable with the row type in which the cursor returns and then opens the cursor. Similarly, the cursor FOR LOOP executes the body of the loop once for each row returned by the query associated with the cursor.Ī nice feature of the cursor FOR LOOP statement is that it allows you to fetch every row from a cursor without manually managing the execution cycle i.e., OPEN, FETCH, and CLOSE. The numeric FOR LOOP executes the body of a loop once for every integer value in a specified range. The cursor FOR LOOP statement is an elegant extension of the numeric FOR LOOP statement. Introduction to PL/SQL cursor FOR LOOP statement Loop raise notice '% - %', rec.release_year, rec.Summary: in this tutorial, you will learn how to use the PL/SQL cursor FOR LOOP statement to fetch and process every record from a cursor. Query := query || 'order by release_year' Įlse raise 'invalid sort type %s', sort_type Query := 'select title, release_year from film ' do $$ declare - sort by 1: title, 2: release year This anonymous block composes the query based on the sort_type variable and uses the for loop to iterate over the row of the result set. We’ll use it in the using clause of the for loop. rec_count: is the number of rows to query from the film table.sort_type: 1 to sort the films by title, 2 to sort the films by release year.The following block shows how to use the for loop statement to loop through a dynamic query. The using clause is used to pass parameters to the query.The query_expression is an SQL statement.The following form of the for loop statement allows you to execute a dynamic query and iterate over its result set: įor row in execute query_expression ] NOTICE: Worst Banger(185 mins) Code language: Shell Session ( shell ) Using PL/pgSQL for loop to iterate over the result set of a dynamic query $$ Code language: PostgreSQL SQL dialect and PL/pgSQL ( pgsql ) NOTICE: Chicago North(185 mins) Limit 10 loop raise notice '%(% mins)', f.title, f.length The following statement uses the for loop to display the titles of the top 10 longest films. The following statement shows how to use the for loop statement to iterate over a result set of a query: NOTICE: Counter 5 Code language: Shell Session ( shell ) Using PL/pgSQL for loop to iterate over a result set It adds 2 to the counter after each iteration: do $$ begin for counter in 1.6 by 2 loop raise notice 'counter: %', counter The following example uses the for loop statement to iterate over six numbers from 1 to 6. NOTICE: Counter: 1 Code language: Shell Session ( shell ) The following example iterates over 5 numbers from 5 to 1 and shows each number in each iteration: do $$ begin for counter in reverse 5.1 loop raise notice 'counter: %', counter NOTICE: Counter: 5 Code language: Shell Session ( shell ) The following example uses the for loop statement to iterate over five numbers from 1 to 5 and display each of them in each iteration: do $$ begin for counter in 1.5 loop raise notice 'counter: %', counter Įnd $$ Code language: PostgreSQL SQL dialect and PL/pgSQL ( pgsql ) The following flowchart illustrates the for loop statement: The for loop evaluates this step expression once only. Third, the step that follows the by keyword specifies the iteration step.The for loop evaluates these expressions before entering the loop. Second, the from and to are expressions that specify the lower and upper bound of the range.However, when you use the reverse option, the for loop subtracts the step from loop_counter. By default, the for loop adds the step to the loop_counter after each iteration. First, the for loop creates an integer variable loop_counter which is accessible inside the loop only. ![]() to loopĮnd loop Code language: PostgreSQL SQL dialect and PL/pgSQL ( pgsql ) The following illustrates the syntax of the forloop statement that loops through a range of integers: įor loop_counter in from. Using PL/pgSQL for loop to iterate over a range of integers Summary: in this tutorial, you will learn about PL/pgSQL for loop statements to iterate over a range of integers or a result set of a query.
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