3.4 Inverse grouping
Let’s assume there is a table ‘orders_news’ that contains the order information of each customer:
customer_id | order_date | product_name |
---|---|---|
1 | 2022-01-01,2022-01-02,2022-01-03 | Product A,Product B,Product C |
2 | 2022-01-01,2022-01-02 | Product D,Product E |
It is required to split one row of data into multiple rows based on the purchase quantity.
SPL
A | |
---|---|
1 | =file(“order_news.txt”).import@t() |
2 | =A1.news(product_name.split(“,”).len();customer_id,date(order_date.split(“,”)(#)):order_date,product_name.split(“,”)(#):product_name) |
The news()is essentially a two-layer loop function. It first loops through A1, then loops through the first parameter product_name.split(“,”).len().
SQL
SELECT customer_id,
TRIM(REGEXP_SUBSTR(order_date, '[^,]+', 1, LEVEL)) AS order_date,
TRIM(REGEXP_SUBSTR(product_name, '[^,]+', 1, LEVEL)) AS product_name
FROM order_news
CONNECT BY LEVEL <= REGEXP_COUNT(product_name, ',') + 1
AND PRIOR customer_id = customer_id
AND PRIOR DBMS_RANDOM.VALUE IS NOT NULL;
Python
Python does not provide the inverse grouping method, so it has to hard code.
4.1 Basic aggregation
Example codes for comparing SPL, SQL, and Python
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