SQL根据列的最大值删除数据

Question

I am looking to delete data from a table based on the max value of an index column - 23. Error received is 'In valid use of group function'

Currently Have:

DELETE FROM Raw_Data 
WHERE
    Raw_Data.Date_Index > MAX(`Date_Index`) - 23

Thanks

Answer 1

You can use JOIN :

DELETE rd
    FROM Raw_Data rd CROSS JOIN
         (SELECT MAX(Date_Index) as maxdi FROM Raw_data) m
    WHERE rd.Date_Index > maxdi - interval 23 days;

Note: This uses CROSS JOIN . You can put the condition in an ON clause instead of a WHERE clause. I'm leaving it in this format because it more closely matches the query in the question.

Answer 2

DELETE FROM Raw_Data 
WHERE
    Raw_Data.Date_Index > (Select MAX(Date_Index) - 23 from Raw_Data)