从日期 sql teradata 过滤去年

Question

please I have a table that contains data from 2020-01-01 till 2021-02-01 and I need to select the data for the running last 12 months to be from 2021-02-01 Back to 2020-02-01 as an example. I need an optimized query as the table has a very huge amount of data 130Millions row

thanks a lot.

Answer 1

Calculate the date range based on CURRENT_DATE, the optimizer resolves this to hard-coded dates:

where datecol between add_months(trunc(current_date, 'mon'),-12)
                  and trunc(current_date, 'mon')

Assuming the table is partitioned by datecol this will result in partition elimination , ie scanning only the required partitions.