Task: Text to Code
Input (English): Step 1: For each row in Candidates table, find corresponding rows in People table and in Candidate_Assessments table.
Step 2: find cell_mobile_number of the results of step 1 whose qualification equals Fail
Output (English): SELECT T1.cell_mobile_number FROM People AS T1 JOIN Candidates AS T2 ON T1.person_id = T2.candidate_id JOIN Candidate_Assessments AS T3 ON T2.candidate_id = T3.candidate_id WHERE T3.qualification = "Fail"