Strange error when casting values using pg-promise

I'm trying to execute this query with pg-promise, version 9.2.1, communicating with Postgres 9.5

All of the following queries work when I run it through the psql CLI or Postico, just not when I run it from pg-promise.

I started off with this query (I know, using pg keywords for fields is bad, but it's for legacy):

await db.many(
`SELECT * FROM "${schemaName}".versions
  UNION
  SELECT * FROM "${schemaName}".z_transfer_metadata
  UNION
  SELECT 'version' AS key, "version"::varchar AS value FROM "${schemaName}".modules WHERE parent_id IS NULL`)

I would get this error from node:

error: syntax error at or near "      SELECT"
 at Connection.parseE (/app/node_modules/pg/lib/connection.js:604:11)
 at Connection.parseMessage (/app/node_modules/pg/lib/connection.js:401:19)

and this from PG:

ERROR:  UNION types character varying and bigint cannot be matched at character 133
STATEMENT:  SELECT * FROM "the_schema".versions 
           UNION 
           SELECT * FROM "the_schema".z_transfer_metadata
           UNION
           SELECT "version" as key, version::varchar as value FROM "the_schema".modules WHERE parent_id IS NULL

The query was working before I added that third union select, so I pared it down to just that query:

`SELECT 'version' AS key, "version"::varchar AS value FROM "${schemaName}".modules WHERE parent_id IS NULL`

but then PG gives me this error:

ERROR:  syntax error at or near "::" at character 35
STATEMENT:  SELECT 'version' AS key, "version"::varchar AS value FROM "the_schema".modules WHERE parent_id IS NULL

I've tried multiple variations, including using CAST and escaping the quotes around 'version', and most of the escaping variations work natively, just not through pg-promise.

ERROR:  syntax error at or near "AS" at character 41
STATEMENT:  SELECT 'version' AS key, CAST("version" AS TEXT) AS value FROM "the_schema".modules WHERE parent_id IS NULL

How can I run this query from pg-promise?

Solution

It turns out I had invalid characters in the query, which was causing very strange output like:

23:17:31 error: relation "schema-d123.modules where parent_id is null" does not exist 
query: SELECT version FROM "schema-d123".modules WHERE parent_id IS NULL

(note how the where clause was being included in the relation name for some reason, despite the query being displayed correctly)

It turns out I had non-breaking spaces in the query somehow, which I discovered moving my cursor through the query by word (option + left / right in VSCode). I installed the Gremlins extension and found that there were in fact invalid characters in the query:

Once I re-typed the query, everything worked as expected.