从postgresql上的current_date中选择上周或周末

SELECT 
    CASE 
        WHEN EXTRACT(dow FROM current_date - interval '7 days') = 0 THEN current_date - interval '7 days'
        WHEN EXTRACT(dow FROM current_date - interval '7 days') = 1 THEN current_date - interval '8 days'
        WHEN EXTRACT(dow FROM current_date - interval '7 days') = 2 THEN current_date - interval '9 days'
        WHEN EXTRACT(dow FROM current_date - interval '7 days') = 3 THEN current_date - interval '10 days'
        WHEN EXTRACT(dow FROM current_date - interval '7 days') = 4 THEN current_date - interval '11 days'
        WHEN EXTRACT(dow FROM current_date - interval '7 days') = 5 THEN current_date - interval '12 days'
        WHEN EXTRACT(dow FROM current_date - interval '7 days') = 6 THEN current_date - interval '13 days'
    END AS previous_weekend;