Hi, Kumar.
4get bout my previous question it is not really necessary.
Try this out and tell me if it solved your problem.
Best,
Oliveiros
UPDATE yourTable
SET "Label" = 1
FROM (
SELECT x."Date" as "Date",x."Village_name" as "Village_name",MAX(y."Date") as anterior
FROM yourTable x
JOIN yourTable y
ON y."Village_name" = x."Village_name"
AND y."Date" < x."Date"
GROUP BY x."Date",x."Village_name"
) umq
WHERE umq."Date" = yourTable."Date"
AND umq."Village_name" = yourTable."Village_name"
AND
yourTable."Date" - umq.anterior > 120
----- Original Message -----
Sent: Friday, June 17, 2011 11:17 AM
Subject: [NOVICE] compare date in two rows
Hi, I have a table with following sample data.
Village_name Date Label
A 1991-01-31 0
A 1991-04-28 0
A 1991-07-15 0
B 2000-02-15 0
B 2000-04-13 0
B 2001-09-13 0
C 1995-07-12 0
C 1995-10-13 0
I need to update the label to 1 when the number of days between two dates(when compared with previous date) is greater than 120 for each village.
Illustration:
For village A: row 1 date will not be compared to any date.
row 2 date will be compared to row 1 date and if satisfies the condition label will be made 1.
row 3 compare to row 2 and continue this till last row for village A.
Similarly first date for village B,C.
