Insert rows into a (postgres) table where the first col is a static value and the second col is the result of a SELECT DISTINCT from another table

I haven't had to use SQL in years and I'm clearly rusty. I have a situation where I'm trying to insert multiple rows into table A. There are two columns of data to be inserted, the first is a "static" value (it is derived but will be the same for all new rows) and the second is the result of a SELECT DISTINCT on table B. There are no relevant constraints on either of the tables that should come into play here. FWIW, this is a sql script in Retool going against a postgres db. _Apologies for the formatting. Table markdown doesn't seem to be working for me_ __Table A__ should look like this at the end: **id** | **source_file** foo | apple.csv foo | banana.csv foo | orange.csv Based on these values in __Table B__ **source_file** apple.csv apple.csv apple.csv banana.csv banana.csv orange.csv orange.csv I've tried a few variations all along the lines of: INSERT INTO table_A (id, source_file) {{id}}, SELECT DISTINCT source_file FROM table_B WHERE source_file IS NOT NULL AND source_file '' Which throws syntax error at or near "$1" And INSERT INTO table_A (id, source_file) SELECT DISTINCT {{id}}, source_file FROM table_B WHERE source_file IS NOT NULL AND source_file '' Which throws insert or update on table "dg_client_data_sources" violates foreign key constraint "fk_data_grid" That second error has me wondering if I need to loop through (gasp!) the results of the SELECT DISTINCT to insert the multiple rows? I may be overthinking that bit.... I can provide other context/examples if needed. Any direction is greatly appreciated!