topic Re: selecting maximum value of an attribute table to create a layer in ArcGIS Pro Questions

selecting maximum value of an attribute table to create a layer

SalvoA — Fri, 08 Oct 2021 18:34:25 GMT

Hi,

I would create an event layer in ArcMap selecting values from a table with a sql query.

In particular I would like to select the row with the maximum value of an attribute, so

I thinked a sql query as:

RealPosition.Easting = ( SELECT MAX ( RealPosition.Easting ) FROM RealPosition )

where RealPosition is the table and Easting is the attributo but the select tool but it says an invalid sql expression was used.

How can I solve?

Thanks.

Re: selecting maximum value of an attribute table to create a layer

JayantaPoddar — Fri, 08 Oct 2021 19:01:30 GMT

In ArcMap, I can open the table > Table Options > Select By Attributes.

Use a similar expression

FIELD_NAME = (SELECT MAX(FIELD_NAME) FROM TABLE_NAME)

Try

Easting = (SELECT MAX(Easting) FROM RealPosition)

Re: selecting maximum value of an attribute table to create a layer

SalvoA — Fri, 08 Oct 2021 20:36:47 GMT

Thanks for your replay.It's work for a simple table, but I have a table joined with another.Could this be the problem?

Re: selecting maximum value of an attribute table to create a layer

JayantaPoddar — Fri, 08 Oct 2021 21:22:10 GMT

Oh!

A similar expression (to your original expression) works for me. My tables are stored in a File Geodatabase.

Re: selecting maximum value of an attribute table to create a layer

SalvoA — Sat, 09 Oct 2021 13:18:43 GMT

Thanks.

The problem is that I used a "join" where a "relate" was needed, so it didn't work.

I have another problem:

I want select max value between rows that have an attribute equal to a value(for example Unit = 'TAB1')Is it possible to do "sequential sql queries "?

Thanks.

Re: selecting maximum value of an attribute table to create a layer

JoshuaBixby — Sat, 09 Oct 2021 18:46:04 GMT

I think I understand the question, but an example using some sample data would be most helpful. If you want to select the maximum value in a group:

ID	Value
A	5
A	2
A	10
B	3
C	4
C	6

It can be possible, but it depends on the back-end data source because SQL support is based on the data source.

Re: selecting maximum value of an attribute table to create a layer

SalvoA — Mon, 11 Oct 2021 08:03:08 GMT

Yes, your example is correct.

what kind of database should I use?

Thanks.