Hi!

I'm not sure if this is a bug or if I'm misunderstanding something, but I can't copy and paste a table that contains an Expression field. The following message appears: “Cannot parse expression for ‘Field’”. This is the first time I've tried pasting a table like this.

Is this a bug or am I using it incorrectly? I'm using version 9.0.182.4.

Based on my recent findings, this is a minor bug. Copying and pasting a table named “Drawing Table”with an expression field works. But it doesn't work if the table has a different name.

I just tried it. I created a Table with a Name field that's nvarchar and a Field field that has the expression

'Sir ' + [Name]

With that table if you have records with John, Paul, George and Ringo in the Name field the Field field shows "Sir John", "Sir Paul", and so on.

I can copy that table and paste it without any problems. That's true whether there are records in the table or no records in the table.

"Cannot parse expression for 'Field'" usually indicates an error in the expression. For example, if you created the above expression using double " quotes instead of single quotes as in

"Sir " + [Name]

...that results in that error.

Thank you, Dimitri, for the clarification, which helped me identify the real problem. The expression works as is in its original form. However, it has a flaw that prevents it from being copied and pasted.

Here is the expression: “Computed field Superf_m² float32 RoundDecs(CoordMeasureArea(CALL CoordMeasureMake(ComponentFieldCoordSystem([Name Table], ‘Geom’), ‘Meter’, TRUE), [Geom]), 3)”

The problem is the [Name Table], which corresponds to the name of the table containing the field with the expression. “ComponentFieldCoordSystem(...” is not appropriate. I'll try to find the right function.

Expressions used in computed fields are SQL, which is very powerful but also given the very broad and deep reach it gives you (lots of functions!) there for sure is plenty to keep in mind as you expand into more sophisticated expressions. There is some new work coming out soon that I think will make it easier to take advantage of SQL. This weekend (probably Sunday) there's a new build coming out with a new feature that will help write SQL with fewer mistakes. After that, probably towards the end of the following week, there will be another addition to the Manifold SQL toolset that could possibly help a lot in terms of finding the right function and writing SQL, including in expressions and not only queries. Stay tuned!

Just to close the loop, the two things that came out which can help: First, build 9.0.182.6 came out and it includes integration with Visual Studio Code that enables you to use VS Code as the editor for queries. The build also includes a VS Code extension that adds full awareness of Manifold SQL Syntax for correct syntax highlighting and about 950 function forms for auto-completion. Both of those help in the nuts and bolts of writing syntactically correct SQL in Manifold. See the What's New page.

The second item that helps is today's release of the Manifold SQL Skill for AI, a package that teaches your AI about Manifold SQL. See my other post at https://georeference.org/forum/t165646.0 .

That's a big help because you can now install the skill and then ask your AI how to write a Manifold query that you want or to write it for you. The skill uses Anthropic's open-sourced specification for skills. It's easiest to install it by default with Claude.ai. Use the free tier of Claude if you don't want to spend for a paid subscription, install the skill, and then ask Claude to write the query for you. Make sure to read the user manual topic on the Manifold SQL skill.