What you are after is essentially an outer join where you include all
records from the grid and link to any records in the points file where
their objects are within the grid objects. Unfortunately MI dosn't support
these joins but you can sort of get around it by doing a table > update
column. With this function, get the value from the points table, join the
grid to the points where the points.obj contains the points.obj, the column
to update is a temporary column, and the value is count.
This will add a temporary column with the number of points that are within
it.
Robert.
Robert Crossley
Trinity Software
10 Trinity Street
Parramatta Park
CAIRNS 4870
AUSTRALIA
Phone: 61-7-40314877
Fax: 61-7-40314810
email: [EMAIL PROTECTED]
web: www.trinitysoftware.com.au
-----Original Message-----
From: J.Smith [SMTP:[EMAIL PROTECTED]]
Sent: Tuesday, 10 August 1999 7:41
To: [EMAIL PROTECTED]
Subject: MI RE: Count with Null Values
Mapinfo List,
This is very simple but I can't work it out....basically I am doing
an SQL select (using MI 4.1) which counts the number of points
within a 350 cell grid - I would like the select to return me the
cells which contain no points so I have sequential output
(a1,a2,a3....) irregardless of whether they contain any points or not
- at the moment it only returns the cells which have points within
it.
Cheers, James Smith
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