IF

Translation reference to convert Teradata IF statement to Snowflake Scripting

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

Description

Provides conditional execution based on the truth value of a condition.

For more information regarding Teradata IF, check here.

IF conditional_expression THEN
     statement
     [ statement ]... 
[ ELSEIF conditional_expression THEN
     statement
     [ statement ]... ]...
[ ELSE   
     statement
     [ statement ]... ]
END IF;

Sample Source Patterns

Sample auxiliar table

Teradata

IN -> Teradata_01.sql

CREATE TABLE if_table(col1 varchar(30));

Snowflake

OUT -> Teradata_01.sql

CREATE TABLE if_table (
col1 varchar(30))
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"teradata"}}'
;

Possible IF variations

Teradata

Code 1

IN -> Teradata_02.sql

CREATE PROCEDURE ifExample1 ( flag NUMBER )
BEGIN
   IF flag = 1 THEN
      INSERT INTO if_table(col1) VALUES ('one');
   END IF;
END;

CALL ifExample1(1);
SELECT * FROM if_table;

Code 2

IN -> Teradata_03.sql

CREATE PROCEDURE ifExample2 ( flag NUMBER )
BEGIN
   IF flag = 1 THEN
      INSERT INTO if_table(col1) VALUES ('one');
   ELSE
      INSERT INTO if_table(col1) VALUES ('Unexpected input.');
   END IF;
END;

CALL ifExample2(2);
SELECT * FROM if_table;

Code 3

IN -> Teradata_04.sql

CREATE PROCEDURE ifExample3 ( flag NUMBER )
BEGIN
   IF flag = 1 THEN
      INSERT INTO if_table(col1) VALUES ('one');
   ELSEIF flag = 2 THEN
      INSERT INTO if_table(col1) VALUES ('two');
   ELSEIF flag = 3 THEN
      INSERT INTO if_table(col1) VALUES ('three');
   END IF;
END;

CALL ifExample3(3);
SELECT * FROM if_table;

Code 4

IN -> Teradata_05.sql

CREATE PROCEDURE ifExample4 ( flag NUMBER )
BEGIN
   IF flag = 1 THEN
      INSERT INTO if_table(col1) VALUES ('one');
   ELSEIF flag = 2 THEN
      INSERT INTO if_table(col1) VALUES ('two');
   ELSEIF flag = 3 THEN
      INSERT INTO if_table(col1) VALUES ('three');
   ELSE
      INSERT INTO if_table(col1) VALUES ('Unexpected input.');  
   END IF;
END;

CALL ifExample4(4);
SELECT * FROM if_table;

Result 1

|COL1|
|----|
|one |

Result 2

|COL1             |
|-----------------|
|Unexpected input.|

Result 3

|COL1 |
|-----|
|three|

Result 4

|COL1             |
|-----------------|
|Unexpected input.|

Snowflake Scripting

Query 1

OUT -> Teradata_02.sql

CREATE OR REPLACE PROCEDURE ifExample1 (FLAG FLOAT)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"teradata"}}'
EXECUTE AS CALLER
AS
$$
   BEGIN
      IF (flag = 1) THEN
         INSERT INTO if_table (col1)
         VALUES ('one');
      END IF;
   END;
$$;

CALL ifExample1(1);

SELECT
   * FROM
   if_table;

Query 2

OUT -> Teradata_03.sql

CREATE OR REPLACE PROCEDURE ifExample2 (FLAG FLOAT)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"teradata"}}'
EXECUTE AS CALLER
AS
$$
   BEGIN
      IF (flag = 1) THEN
         INSERT INTO if_table (col1)
         VALUES ('one');
      ELSE
         INSERT INTO if_table (col1)
         VALUES ('Unexpected input.');
      END IF;
   END;
$$;

CALL ifExample2(2);

SELECT
   * FROM
   if_table;

Query 3

OUT -> Teradata_04.sql

CREATE OR REPLACE PROCEDURE ifExample3 (FLAG FLOAT)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"teradata"}}'
EXECUTE AS CALLER
AS
$$
   BEGIN
      IF (flag = 1) THEN
         INSERT INTO if_table (col1)
         VALUES ('one');
      ELSEIF (flag = 2) THEN
         INSERT INTO if_table (col1)
         VALUES ('two');
      ELSEIF (flag = 3) THEN
         INSERT INTO if_table (col1)
         VALUES ('three');
      END IF;
   END;
$$;

CALL ifExample3(3);

SELECT
   * FROM
   if_table;

Query 4

OUT -> Teradata_05.sql

CREATE OR REPLACE PROCEDURE ifExample4 (FLAG FLOAT)
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"teradata"}}'
EXECUTE AS CALLER
AS
$$
   BEGIN
      IF (flag = 1) THEN
         INSERT INTO if_table (col1)
         VALUES ('one');
      ELSEIF (flag = 2) THEN
         INSERT INTO if_table (col1)
         VALUES ('two');
      ELSEIF (flag = 3) THEN
         INSERT INTO if_table (col1)
         VALUES ('three');
      ELSE
         INSERT INTO if_table (col1)
         VALUES ('Unexpected input.');
      END IF;
   END;
$$;

CALL ifExample4(4);

SELECT
   * FROM
   if_table;

Result 1

|COL1|
|----|
|one |

Result 2

|COL1             |
|-----------------|
|Unexpected input.|

Result 3

|COL1 |
|-----|
|three|

Result 4

|COL1             |
|-----------------|
|Unexpected input.|