Question

I am getting this error in Google BigQuery:

Error: Ambiguous field reference in SELECT clause. (Remember to fully qualify all field names in the SELECT clause as <table.field>.)

My query is

SELECT LoanPerf1.loankey, Loans.Key
FROM   prosperloans1.LoanPerf1
JOIN   prosperloans1.Loans
       ON LoanPerf1.loankey = Loans.Key

prosperloans1 is the dataset id
the 2 table names are correct.
the error returns regardless of which field name appears first in the select clause.

The documentation on Google SQL Syntax says this is correct:

// Simple JOIN of two tables
SELECT table1.id, table2.username
FROM   table1
JOIN   table2
       ON table1.name = table2.name AND table1.id = table2.customer_id;

Thanks
Shawn

Answer 1

Try adding an AS clause to the table names:

SELECT LoanPerf1.loankey, Loans.Key
FROM prosperloans1.LoanPerf1 as LoanPerf1
JOIN prosperloans1.Loans as Loans
ON LoanPerf1.loankey = Loans.Key