DECLARE REFCURSOR

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Description

A refcursor data type simply holds a reference to a cursor. You can create a cursor variable by declaring it as a variable of type refcursor

(Redshift SQL Language Reference Refcursor Declaration)

Refcursor declarations are fully supported by Snowflake.

Grammar Syntax

DECLARE
name refcursor;

Since Snowflake does not support the REFCURSOR data type, its functionality is replicated by converting the REFCURSOR variable into a RESULTSET type. The query used to open the REFCURSOR is assigned to the RESULTSET variable, after which a new cursor is created and linked to the RESULTSET variable. Additionally, all references to the original REFCURSOR within the cursor logic are updated to use the new cursor, thereby replicating the original functionality.

Sample Source Patterns

Case: Single use

Input Code:

Redshift

IN -> Redshift_01.sql

CREATE OR REPLACE PROCEDURE VARIABLE_REFCURSOR()
LANGUAGE plpgsql
AS $$
DECLARE
  v_curs1 refcursor;
BEGIN
  OPEN v_curs1 FOR SELECT column1_name, column2_name FROM your_table;
-- Cursor logic
  CLOSE v_curs1;
 END;
$$;

Output Code:

Snowflake

OUT -> Redshift_01.sql

CREATE OR REPLACE PROCEDURE VARIABLE_REFCURSOR ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "redshift",  "convertedOn": "03/03/2025",  "domain": "test" }}'
AS $$
  DECLARE
   v_curs1 RESULTSET;
BEGIN
   v_curs1 := (
    SELECT column1_name, column2_name FROM your_table
   );
   LET v_curs1_Resultset_1 CURSOR
   FOR
    v_curs1;
   OPEN v_curs1_Resultset_1;
-- Cursor logic
  CLOSE v_curs1_Resultset_1;
 END;
$$;

Case: Cursor with Dynamic Sql

Input Code:

Redshift

IN -> Redshift_02.sql

CREATE OR REPLACE PROCEDURE VARIABLE_REFCURSOR_DYNAMIC(min_salary NUMERIC)
LANGUAGE plpgsql
AS $$
DECLARE
    cur refcursor;
    qry TEXT;
BEGIN
    qry := 'SELECT id, name FROM employees WHERE salary > ' || min_salary;

    OPEN cur FOR EXECUTE qry;
-- Cursor logic
    CLOSE cur;
END;
$$;


CREATE OR REPLACE PROCEDURE VARIABLE_REFCURSOR_DYNAMIC2(min_salary NUMERIC)
LANGUAGE plpgsql
AS $$
DECLARE
    cur refcursor;
BEGIN
    OPEN cur FOR EXECUTE 'SELECT id, name FROM employees WHERE salary > ' || min_salary;
-- Cursor logic
    CLOSE cur;
END;
$$;

Output Code:

Redshift

OUT -> Redshift_02.sql

CREATE OR REPLACE PROCEDURE VARIABLE_REFCURSOR_DYNAMIC (min_salary NUMERIC)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "redshift",  "convertedOn": "03/03/2025",  "domain": "test" }}'
AS $$
        DECLARE
            cur RESULTSET;
    qry TEXT;
BEGIN
    qry := 'SELECT id, name FROM employees WHERE salary > ' || min_salary;
            cur := (
                EXECUTE IMMEDIATE qry
            );
            LET cur_Resultset_1 CURSOR
            FOR
                cur;
            OPEN cur_Resultset_1;
-- Cursor logic
    CLOSE cur_Resultset_1;
END;
$$;


CREATE OR REPLACE PROCEDURE VARIABLE_REFCURSOR_DYNAMIC2 (min_salary NUMERIC)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "redshift",  "convertedOn": "03/03/2025",  "domain": "test" }}'
AS $$
        DECLARE
            cur RESULTSET;
BEGIN
            cur := (
                EXECUTE IMMEDIATE 'SELECT id, name FROM employees WHERE salary > ' || min_salary
            );
            LET cur_Resultset_2 CURSOR
            FOR
                cur;
            OPEN cur_Resultset_2;
-- Cursor logic
    CLOSE cur_Resultset_2;
END;
$$;

Case: Multiple uses:

Input Code:

Redshift

IN -> Redshift_03.sql

CREATE OR REPLACE PROCEDURE VARIABLE_REFCURSOR()
LANGUAGE plpgsql
AS $$
DECLARE
  v_curs1 refcursor;
BEGIN
  OPEN v_curs1 FOR SELECT column1_name, column2_name FROM your_table;
-- Cursor logic
  CLOSE v_curs1;
  OPEN v_curs1 FOR SELECT column3_name, column4_name FROM your_table2;
-- Cursor logic
  CLOSE v_curs1;
 END;
$$;

Output Code:

Snowflake

OUT -> Redshift_03.sql

CREATE OR REPLACE PROCEDURE VARIABLE_REFCURSOR ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "redshift",  "convertedOn": "03/03/2025",  "domain": "test" }}'
AS $$
  DECLARE
   v_curs1 RESULTSET;
BEGIN
   v_curs1 := (
    SELECT column1_name, column2_name FROM your_table
   );
   LET v_curs1_Resultset_1 CURSOR
   FOR
    v_curs1;
   OPEN v_curs1_Resultset_1;
-- Cursor logic
  CLOSE v_curs1_Resultset_1;
   v_curs1 := (
    SELECT column3_name, column4_name FROM your_table2
   );
   LET v_curs1_Resultset_2 CURSOR
   FOR
    v_curs1;
   OPEN v_curs1_Resultset_2;
-- Cursor logic
  CLOSE v_curs1_Resultset_2;
 END;
$$;

Known Issues

There are no known issues.

Related EWIs.

There are no related EWIs.