trying to concat in the RAISE() function using || results in a syntax error

Question

relevant documentation

I am trying to create a trigger that catches inserts into the Viewings table where the foreign key (viewings.location) does not correspond to

Answer 1

In the SQLite grammar, the second parameter of the RAISE() expression is not a string but a name:

RAISE(ABORT, some_error)

Identifiers can be quoted with double quotes, and for historical reasons, SQLite accepts a string (with single quotes) where an identifier is expected, but then it must be a single string, not a string expression composed of other values:

RAISE(ABORT, "some error")

There is no mechanism to get a dynamic value into the error message, except by creating a user-defined function for this.