COMPOUND STATEMENTS

This section is a translation specification for the compound statements

Some parts in the output code are omitted for clarity reasons.

General description

The basic unit of a PL/SQL source program is the block, which groups related declarations and statements.

A PL/SQL block is defined by the keywords DECLARE, BEGIN, EXCEPTION, and END. These keywords divide the block into a declarative part, an executable part, and an exception-handling part. Only the executable part is required. (PL/SQL Anonymous Blocks)

The BEGIN...END block in Oracle can have the following characteristics:

  1. Be nested.

  2. Contain the DECLARE statement for variables.

  3. Group multiple SQL or PL/SQL statements.

Oracle syntax

[DECLARE <Variable declaration>]
BEGIN
  <Executable statements>
[EXCEPTION <Exception handler>]
END

Snowflake syntax

BEGIN
    <statement>;
    [ <statement>; ... ]
[ EXCEPTION <exception_handler> ]
END;

In Snowflake, a BEGIN/END block can be the top-level construct inside an anonymous block (Snowflake documentation).

Sample Source Patterns

1. IF-ELSE block

Review the following documentation about IF statements to learn more: SnowConvert IF statements translation and Snowflake IF statement documentation

Oracle

IN -> Oracle_01.sql
DECLARE
    age NUMBER := 18;
BEGIN
    IF age >= 18 THEN 
        DBMS_OUTPUT.PUT_LINE('You are an adult.');
    ELSE 
        DBMS_OUTPUT.PUT_LINE('You are a minor.');
    END IF;
END;

Snowflake

OUT -> Oracle_01.sql
DECLARE
    age NUMBER(38, 18) := 18;
    call_results VARIANT;
BEGIN
    IF (:age >= 18) THEN
        --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
        call_results := (
            CALL DBMS_OUTPUT.PUT_LINE_UDF('You are an adult.')
        );
    ELSE
        --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
        call_results := (
            CALL DBMS_OUTPUT.PUT_LINE_UDF('You are a minor.')
        );
    END IF;
    RETURN call_results;
END;

2. CASE statement

For more information, review the following documentation: SnowConvert CASE statement documentation and Snowflake CASE documentation

Oracle

IN -> Oracle_02.sql
BEGIN
   DECLARE
      day_of_week NUMBER := 3;
   BEGIN
      CASE day_of_week
         WHEN 1 THEN DBMS_OUTPUT.PUT_LINE('Sunday');
         WHEN 2 THEN DBMS_OUTPUT.PUT_LINE('Monday');
         WHEN 3 THEN DBMS_OUTPUT.PUT_LINE('Tuesday');
         WHEN 4 THEN DBMS_OUTPUT.PUT_LINE('Wednesday');
         WHEN 5 THEN DBMS_OUTPUT.PUT_LINE('Thursday');
         WHEN 6 THEN DBMS_OUTPUT.PUT_LINE('Friday');
         WHEN 7 THEN DBMS_OUTPUT.PUT_LINE('Saturday');
         ELSE DBMS_OUTPUT.PUT_LINE('Invalid day');
      END CASE;
   END;
END;

Snowflake

OUT -> Oracle_02.sql
DECLARE
   call_results VARIANT;
BEGIN
   DECLARE
      day_of_week NUMBER(38, 18) := 3;
   BEGIN
      CASE :day_of_week
         WHEN 1 THEN
            --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
            call_results := (
               CALL DBMS_OUTPUT.PUT_LINE_UDF('Sunday')
            );
         WHEN 2 THEN
            --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
            call_results := (
               CALL DBMS_OUTPUT.PUT_LINE_UDF('Monday')
            );
         WHEN 3 THEN
            --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
            call_results := (
               CALL DBMS_OUTPUT.PUT_LINE_UDF('Tuesday')
            );
         WHEN 4 THEN
            --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
            call_results := (
               CALL DBMS_OUTPUT.PUT_LINE_UDF('Wednesday')
            );
         WHEN 5 THEN
            --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
            call_results := (
               CALL DBMS_OUTPUT.PUT_LINE_UDF('Thursday')
            );
         WHEN 6 THEN
            --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
            call_results := (
               CALL DBMS_OUTPUT.PUT_LINE_UDF('Friday')
            );
         WHEN 7 THEN
            --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
            call_results := (
               CALL DBMS_OUTPUT.PUT_LINE_UDF('Saturday')
            );
         ELSE
            --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
            call_results := (
               CALL DBMS_OUTPUT.PUT_LINE_UDF('Invalid day')
            );
      END CASE;
   END;
   RETURN call_results;
END;

3. LOOP statements

For more information review the following documentation: SnowConvert FOR LOOP and Snowflake LOOP documentation and FOR documentation.

Oracle

IN -> Oracle_03.sql
BEGIN
    FOR i IN 1..10 LOOP
        NULL;
    END LOOP;
END;

Snowflake

OUT -> Oracle_03.sql
BEGIN
    FOR i IN 1 TO 10 LOOP
        NULL;
    END LOOP;
END;

4. Procedure call and OUTPUT parameters

Anonymous block in Oracle may have calls to procedures. Furthermore, the following documentation may be useful: SnowConvert Procedure documentation.

The following example uses the OUT parameters, the information about the current transformation can be found here: SnowConvert OUTPUT Parameters

Oracle

IN -> Oracle_04.sql
-- Procedure declaration
CREATE OR REPLACE PROCEDURE calculate_sum(
    p_num1 IN NUMBER,
    p_num2 IN NUMBER,
    p_result OUT NUMBER
)
IS
BEGIN
    -- Calculate the sum of the two numbers
    p_result := p_num1 + p_num2;
END;
/

-- Anonymous block with a procedure call
DECLARE
    -- Declare variables to hold the input and output values
    v_num1 NUMBER := 10;
    v_num2 NUMBER := 20;
    v_result NUMBER;
BEGIN
    -- Call the procedure with the input values and get the result
    calculate_sum(v_num1, v_num2, v_result);
    
    -- Display the result
    DBMS_OUTPUT.PUT_LINE('The sum of ' || v_num1 || ' and ' || v_num2 || ' is ' || v_result);
END;
/

Snowflake

OUT -> Oracle_04.sql
-- Procedure declaration
CREATE OR REPLACE PROCEDURE calculate_sum (p_num1 NUMBER(38, 18), p_num2 NUMBER(38, 18), p_result NUMBER(38, 18)
)
RETURNS VARIANT
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"oracle"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
    -- Calculate the sum of the two numbers
        p_result := :p_num1 + :p_num2;
        RETURN p_result;
    END;
$$;

-- Anonymous block with a procedure call
DECLARE
    -- Declare variables to hold the input and output values
    v_num1 NUMBER(38, 18) := 10;
    v_num2 NUMBER(38, 18) := 20;
    v_result NUMBER(38, 18);
    call_results VARIANT;
BEGIN
    call_results := (
        CALL
        -- Call the procedure with the input values and get the result
        calculate_sum(:v_num1, :v_num2, :v_result)
    );
    v_result := :call_results;

    -- Display the result
    --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
    call_results := (
        CALL DBMS_OUTPUT.PUT_LINE_UDF('The sum of ' || NVL(:v_num1 :: STRING, '') || ' and ' || NVL(:v_num2 :: STRING, '') || ' is ' || NVL(:v_result :: STRING, ''))
    );
    RETURN call_results;
END;

5. Alter session

For more information, review the following documentation: Alter session documentation.

Notice that in Oracle, the block BEGIN...END should use the EXECUTE IMMEDIATE statement to run alter session statements.

Oracle

IN -> Oracle_05.sql
DECLARE
     lv_sql_txt VARCHAR2(200);
BEGIN
     lv_sql_txt := 'ALTER SESSION SET nls_date_format = ''DD-MM-YYYY''';
     EXECUTE IMMEDIATE lv_sql_txt;
END;

Snowflake

OUT -> Oracle_05.sql
DECLARE
     lv_sql_txt VARCHAR(200);
BEGIN
     lv_sql_txt := 'ALTER SESSION SET nls_date_format = ''DD-MM-YYYY''';
     !!!RESOLVE EWI!!! /*** SSC-EWI-0030 - THE STATEMENT BELOW HAS USAGES OF DYNAMIC SQL. ***/!!!!!!RESOLVE EWI!!! /*** SSC-EWI-0027 - THE FOLLOWING STATEMENT USES A VARIABLE/LITERAL WITH AN INVALID QUERY AND IT WILL NOT BE EXECUTED ***/!!! 
     EXECUTE IMMEDIATE :lv_sql_txt;
END;

6. Cursors

The following example displays the usage of a cursor inside a BEGIN...END block. Review the following documentation to learn more: Cursor documentation.

Oracle

IN -> Oracle_06.sql
CREATE TABLE employee (
    ID_Number	NUMBER,
    emp_Name	VARCHAR(200),
    emp_Phone	NUMBER
);

INSERT INTO employee VALUES (1, 'NameA NameZ', 1234567890);
INSERT INTO employee VALUES (2, 'NameB NameY', 1234567890);

DECLARE
    var1 VARCHAR(20);
    CURSOR cursor1 IS SELECT emp_Name FROM employee ORDER BY ID_Number;
BEGIN
    OPEN cursor1;
    FETCH cursor1 INTO var1;
    CLOSE cursor1;
	DBMS_OUTPUT.PUT_LINE(var1);
END;

Snowflake

OUT -> Oracle_06.sql
CREATE OR REPLACE TABLE employee (
	   ID_Number NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/,
	   emp_Name	VARCHAR(200),
	   emp_Phone NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/
)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"oracle"}}'
;

INSERT INTO employee
VALUES (1, 'NameA NameZ', 1234567890);

INSERT INTO employee
VALUES (2, 'NameB NameY', 1234567890);

DECLARE
    var1 VARCHAR(20);
	   cursor1 CURSOR
	   FOR
		SELECT emp_Name FROM
			employee
		ORDER BY ID_Number;
	   call_results VARIANT;
BEGIN
	   OPEN cursor1;
	   FETCH cursor1 INTO
		:var1;
	   CLOSE cursor1;
	   --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
	   call_results := (
		CALL DBMS_OUTPUT.PUT_LINE_UDF(:var1)
	   );
	   RETURN call_results;
END;

7. Select statements

For more information review the following documentation: Select documentation.

Oracle

IN -> Oracle_07.sql
CREATE TABLE employee (
    ID_Number NUMBER,
    emp_Name VARCHAR(200),
    emp_Phone NUMBER
);

INSERT INTO employee VALUES (1, 'NameA NameZ', 1234567890);
INSERT INTO employee VALUES (2, 'NameB NameY', 1234567890);

DECLARE
    var_Result NUMBER;
BEGIN
    SELECT COUNT(*) INTO var_Result FROM employee;
    DBMS_OUTPUT.PUT_LINE(var_Result);
END;

Snowflake

OUT -> Oracle_07.sql
CREATE OR REPLACE TABLE employee (
       ID_Number NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/,
       emp_Name VARCHAR(200),
       emp_Phone NUMBER(38, 18) /*** SSC-FDM-0006 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE. ***/
   )
   COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"oracle"}}'
   ;

   INSERT INTO employee
   VALUES (1, 'NameA NameZ', 1234567890);

   INSERT INTO employee
   VALUES (2, 'NameB NameY', 1234567890);

   DECLARE
    var_Result NUMBER(38, 18);
       call_results VARIANT;
   BEGIN
       SELECT COUNT(*) INTO
           :var_Result
       FROM
           employee;
       --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
       call_results := (
           CALL DBMS_OUTPUT.PUT_LINE_UDF(:var_Result)
       );
       RETURN call_results;
   END;

8. Join Statements

For more information review the following documentation: Joins documentation.

Oracle

IN -> Oracle_08.sql
CREATE TABLE t1 (col1 INTEGER);
CREATE TABLE t2 (col1 INTEGER);

INSERT INTO t1 (col1) VALUES (2);
INSERT INTO t1 (col1) VALUES (3);
INSERT INTO t1 (col1) VALUES (4);

INSERT INTO t2 (col1) VALUES (1);
INSERT INTO t2 (col1) VALUES (2);
INSERT INTO t2 (col1) VALUES (2);
INSERT INTO t2 (col1) VALUES (3);


DECLARE
    total_price FLOAT;
    CURSOR cursor1 IS SELECT t1.col1 as FirstTable, t2.col1 as SecondTable
    FROM t1 INNER JOIN t2
        ON t2.col1 = t1.col1
    ORDER BY 1,2;
BEGIN
    total_price := 0.0;
    FOR rec IN cursor1 LOOP
      total_price := total_price + rec.FirstTable;
    END LOOP;
    DBMS_OUTPUT.PUT_LINE(total_price);
END;

Snowflake

OUT -> Oracle_08.sql
CREATE OR REPLACE TABLE t1 (col1 INTEGER)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"oracle"}}'
;

CREATE OR REPLACE TABLE t2 (col1 INTEGER)
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},"attributes":{"component":"oracle"}}'
;

INSERT INTO t1(col1) VALUES (2);

INSERT INTO t1(col1) VALUES (3);

INSERT INTO t1(col1) VALUES (4);

INSERT INTO t2(col1) VALUES (1);

INSERT INTO t2(col1) VALUES (2);

INSERT INTO t2(col1) VALUES (2);

INSERT INTO t2(col1) VALUES (3);

DECLARE
    total_price FLOAT;
    cursor1 CURSOR
    FOR
        SELECT t1.col1 as FIRSTTABLE, t2.col1 as SECONDTABLE
           FROM
            t1
            INNER JOIN
                t2
               ON t2.col1 = t1.col1
           ORDER BY 1,2;
    call_results VARIANT;
BEGIN
    total_price := 0.0;
    OPEN cursor1;
    --** SSC-PRF-0004 - THIS STATEMENT HAS USAGES OF CURSOR FOR LOOP **
    FOR rec IN cursor1 DO
        total_price :=
        !!!RESOLVE EWI!!! /*** SSC-EWI-OR0036 - TYPES RESOLUTION ISSUES, ARITHMETIC OPERATION '+' MAY NOT BEHAVE CORRECTLY BETWEEN AproxNumeric AND unknown ***/!!!
        :total_price + rec.FIRSTTABLE;
    END FOR;
    CLOSE cursor1;
    --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
    call_results := (
        CALL DBMS_OUTPUT.PUT_LINE_UDF(:total_price)
    );
    RETURN call_results;
END;

9. Exception handling

Oracle

IN -> Oracle_09.sql
DECLARE
      v_result NUMBER;
BEGIN
   v_result := 1 / 0;
   EXCEPTION
      WHEN ZERO_DIVIDE THEN
         DBMS_OUTPUT.PUT_LINE( SQLERRM );
END;

Snowflake

OUT -> Oracle_09.sql
DECLARE
      v_result NUMBER(38, 18);
      error_results VARIANT;
BEGIN
      v_result := 1 / 0;
   EXCEPTION
      WHEN ZERO_DIVIDE THEN
      --** SSC-FDM-OR0035 - CHECK UDF IMPLEMENTATION FOR DBMS_OUTPUT.PUT_LINE_UDF. **
      error_results := (
         CALL DBMS_OUTPUT.PUT_LINE_UDF( SQLERRM )
      );
      RETURN error_results;
END;

Known issues

  1. Exceptions that use GOTO statements may be affected too.

  2. Cursor functionality may be adapted under current restrictions on translations.

  1. SSC-EWI-0027:The following statement uses a variable/literal with an invalid query and it will not be executed.

  2. SSC-EWI-OR0036: Types resolution issues, the arithmetic operation may not behave correctly between string and date.

  3. SSC-FDM-OR0035: DBMS_OUTPUT.PUTLINE check UDF implementation.

  4. SSC-FDM-0006: Number type column may not behave similarly in Snowflake.

  5. SSC-PRF-0004: This statement has usages of cursor for loop.

  6. SSC-EWI-0030: The statement below has usages of dynamic SQL

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