使用 sql 删除记录，如果它大于某个数字并附加一个单位（例如 3M 或 3cm）

Question

let a table be 'hotel', with a column:

hotel_worth
15M
4M
8M
3M
1M
2M
11M

how do i delete the records in the table using sql,where worth is greater than 3M.

Answer 1

In the WHERE clause of the DELETE statement you can convert the string to a numeric value by adding 0 :

DELETE FROM hotel
WHERE hotel_worth + 0 > 3

If you want to delete only rows with the suffix M (if there are other suffixes also) add:

AND RIGHT(hotel_worth, 1) = 'M'

Answer 2

This can be done by using:

DELETE FROM price 
WHERE SUBSTR(`hotel_worth`, 1, LENGTH(`hotel_worth`) - 1) + 0 > 3

Explanation: the substr function:

SUBSTR(`hotel_worth`, 1, LENGTH(`hotel_worth`) - 1)

retrieves the data of the column excluding the last character ie (from 10M to 10), then the + 0 to it converts it to int.

So the > 3 comparison at the end basically means selecting data that are greater than 3M.