churn=# update churn_trend set ov_churn_rate=tre.previous from (SELECT (select
total_customer from churn_trend as ct2 where ct2.month=churn_trend.month-1)-tota
l_customer AS previous from churn_trend) as tre where month>=2;
UPDATE 11
churn=# select month,total_customer,ov_churn_rate from churn_trend;
month | total_customer | ov_churn_rate
-------+----------------+---------------
1 | 136281 | 0
2 | 119885 |
3 | 109434 |
4 | 101730 |
5 | 95593 |
6 | 90426 |
7 | 86009 |
8 | 82687 |
9 | 79180 |
10 | 75991 |
11 | 73245 |
12 | 70587 |
(12 rows)
here i got 11 updates but when i try to retrieve the data nothing is there?
why it is pls tell me