postgresql7.1 select variable_name, to_char(avg(sum_score), '9999.9') as mean_score, min(sum_score) as min_score, max(sum_score) as max_score, count(sum_score) as count_score, coalesce(to_char(stddev_samp(sum_score), '9999.9'), '0.0') as sd_score from (select variable_name, sum(score) as sum_score from survsimp_choice_scores, survsimp_question_responses, survsimp_variables, survsimp_responses where survsimp_choice_scores.choice_id = survsimp_question_responses.choice_id and survsimp_choice_scores.variable_id = survsimp_variables.variable_id and survsimp_responses.response_id = survsimp_question_responses.response_id and survey_id = :local_survey_id group by survsimp_responses.response_id, variable_name) group by variable_name