mismatched input

[#1]

Can anyone tell me what I'm doing wrong. 

I'm getting the following error from the table creation below - 

FAILED: ParseException line 8:37 mismatched input 'TREX' expecting ) near ''\\', bp.step_parameter_name) \n
WHERE prm.data_source = '' in function specification")

CREATE TABLE new_table AS SELECT DISTINCT
prm.source AS source,
bp.process_stage AS process_stage
FROM table1 AS prm
LEFT JOIN table2 AS bp
ON (prm.parameter = CONCAT(bp.step_path, '\\', bp.step_parameter_name))
WHERE (prm.data_source = 'TDATA' OR prm.data_source = 'Docs')

[#2 · Accepted solution]

Disregard; syntax is good.  I was using Python's f-string and forgot to escape the backslash.