如何使用SQL从格式化的字母数字字符串中提取第一和第二个数字？

Question

Example data in a weight column (from 3 rows of data)

+-------------------------+
| weight                  |
+-------------------------+
| Pump:398kg Motor:0kg    |
| Pump:448# Motor:997#    |
| Pump:355kg Motor:2495kg |
+-------------------------+

Is there a way to extract the first number from column, and the 2nd number in the column separately?

Note

• string will always start with Pump:
• string Motor: will always be in the middle
• denomination delimiter is either # or kg , there are no others
• weight is always an integer

My goal is to split the numbers each into their own column

ie

UPDATE table set weight_pump = ?, weight_motor = ?
UPDATE table set weight_pump = 398, weight_motor = 0

I can solve this using PHP (SELECT each row, do REGEX to extract numbers, write back to the row)

But what I am looking for is a pure SQL solution, if such exists. Preferably a single SQL statement, if exists but I am not opposed to several statements or intermediate steps.

I have seen other answers but they focus on extracting a single number from SQL, I am seeking something more powerful.

Note: it can be also done in two steps (one for "kg", one for "#") to simplify query.

Answer 1

Here's a solution, using substring_index().

I like this function because it doesn't depend so much on specific character positions.

mysql> SELECT
  SUBSTRING_INDEX(SUBSTRING_INDEX(SUBSTRING_INDEX(weight, ':', -2), 'kg', 1), '#', 1) AS weight_pump,
  SUBSTRING_INDEX(SUBSTRING_INDEX(SUBSTRING_INDEX(weight, ':', -1), 'kg', 1), '#', 1) AS weight_motor 
FROM MyTable;

Output:

+-------------+--------------+
| weight_pump | weight_motor |
+-------------+--------------+
| 398         | 0            |
| 448         | 997          |
| 355         | 2495         |
+-------------+--------------+

This works with UPDATE too:

mysql> UPDATE MyTable
  SET weight_pump = SUBSTRING_INDEX(SUBSTRING_INDEX(SUBSTRING_INDEX(weight, ':', -2), 'kg', 1), '#', 1),
      weight_motor = SUBSTRING_INDEX(SUBSTRING_INDEX(SUBSTRING_INDEX(weight, ':', -1), 'kg', 1), '#', 1);

Read more about this function here: http://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_substring-index