Hey @Dhof — thanks for posting and welcome to the forum!
This is a non-obvious issue with the way Postgres expects array syntax and the default way Retool handles arrays in Javascript.
In order to update a Postgres array column, you'll need to transform the JS array to a Postgres array, doing something like this:
{ {{ multiselect.value.map(x => `"${x}"`).join(",") }} }
Here's a working example (this is double confusing because we display the array in the table like Javascript, but Postgres requires a different format):
