透過表別名區分同一張表的不同角色,輕鬆實現雙欄位關聯:
SELECT a.man_id, man_name, d.sex_name, zw_name, c.money
FROM man AS a
LEFT JOIN zw AS b ON a.zw_id = b.zw_id
LEFT JOIN zw AS c ON a.man_id = c.man_id -- 同表不同別名
LEFT JOIN xb AS d ON c.sex_id = d.sex_id;
關鍵在於為同一張表指派不同別名(b、c),各自承擔不同的關聯邏輯。