Hi Clemens, thanks for that.
Unfortunately is comlains after "SET diff_used," and I get "near ",":
syntax error: "
If I seperate it out into stand-alone statemeonts like this:
UPDATE tmp_dspace_import
SET diff_used = (SELECT tmp_dspace_import.used_mb - ifnull(prev.used_mb, 0)
FROM tmp_dspace_import AS prev WHERE prev.date_time <
tmp_dspace_import.date_time ORDER BY date_time DESC LIMIT 1),
diff_free = (SELECT tmp_dspace_import.free_mb - ifnull(prev.free_mb, 0)
FROM tmp_dspace_import AS prev WHERE prev.date_time <
tmp_dspace_import.date_time ORDER BY date_time DESC LIMIT 1),
diff_free_pc = (SELECT tmp_dspace_import.free_pc - ifnull(prev.free_pc,
0) FROM tmp_dspace_import AS prev WHERE prev.date_time <
tmp_dspace_import.date_time ORDER BY date_time DESC LIMIT 1);
then it comes back "no error:" but doesn't update anything. Not sure if
the abokve is ok - looks ok to me. The only question in my mind is that it
won't diferentiate between servers and drives.SOme only have a C drive but
most hace a D and E, some have an F. All local drives btw, not mapped.
On Tue, Aug 22, 2017 at 10:32 AM, Clemens Ladisch <clem...@ladisch.de>
wrote:
> Matthew Halliday wrote:
> > I used the SQLite Studio to create the table so used the DATETIME data
> type
> > for that, and although I used yyyy-mm-dd hh:mm:ss in the script
>
> That is correct.
>
> > it seems to have reverted it to dd/mm/yy hh:mm:ss.
>
> That would not be usable.
> Check the actual format with the sqlite3 command-line shell.
>
>
> Assuming the timestamp format is usable, you can compute the differences
> with a statement like this:
>
> -- add three columns; then:
> UPDATE MyTable
> SET (diff_used, diff_free, diff_free_pc)
> = (SELECT MyTable.used_mb - ifnull(prev.used_mb, 0),
> MyTable.free_mb - ifnull(prev.free_mb, 0),
> MyTable.free_pc - ifnull(prev.free_pc, 0)
> FROM MyTable AS prev
> WHERE prev.date_time < MyTable.date_time
> ORDER BY date_time DESC
> LIMIT 1);
>
> This is much faster if there is an index on date_time.
>
>
> Regards,
> Clemens
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