Teradata : Sum up values in a column - sql

Question

Problem Statement
Example is shown in below image :
The last 2 rows have the patterns like "1.283 2 3" in a single cell. The numbers are seperated by space in the column. We need to add those nos and represent in the format given in Output.
So, the cell having "1.283 2 3" must be converted to 6.283
Challenges facing :
The column values are in string format.
Add nos after casting them into integer
Donot want to take data in UNIX box and manipulate the same.

Answer 1

In TD14 there would be a built-in table UDF named STRTOK_SPLIT_TO_TABLE, before you need to implement your own UDF or use a recursive query.
I modified an existing string splitting script to use blanks as delimiter:
CREATE VOLATILE TABLE Strings
(
groupcol INT NOT NULL,
string VARCHAR(991) NOT NULL
) ON COMMIT PRESERVE ROWS;
INSERT INTO Strings VALUES (1,'71.792');
INSERT INTO Strings VALUES (2,'71.792 1 2');
INSERT INTO Strings VALUES (3,'1.283 2 3');
WITH RECURSIVE cte
(groupcol,
--string,
len,
remaining,
word,
pos
) AS (
SELECT
GroupCol,
--String,
POSITION(' ' IN String || ' ') - 1 AS len,
TRIM(LEADING FROM SUBSTRING(String || ' ' FROM len + 2)) AS remaining,
TRIM(SUBSTRING(String FROM 1 FOR len)) AS word,
1
FROM strings
UNION ALL
SELECT
GroupCol,
--String,
POSITION(' ' IN remaining)- 1 AS len_new,
TRIM(LEADING FROM SUBSTRING(remaining FROM len_new + 2)),
TRIM(SUBSTRING(remaining FROM 1 FOR len_new)),
pos + 1
FROM cte
WHERE remaining <> ''
)
SELECT
groupcol,
-- remove the NULLIF to get 0 for blank strings
SUM(CAST(NULLIF(word, '') AS DECIMAL(18,3)))
FROM cte
GROUP BY 1
This might use a lot of spool, hopefully you're not running that on a large table.