摘要： SELECT FROM TABLE_A WHERE TABLE_A.ID NOT IN(SELECT FOREN_ID FROM TABLE_B)SELECT FROM TABLE_A WHERE TABLE_A.ID IN(SELECT FOREN_ID FROM TABLE_B)not in的时候 如果SELECT FOREN_ID FROM TABLE_B 返回的值有NULL值的话，则整个语句SELECT FROM TABLE_A WHERE TABLE_A.ID NOT IN(SELECT FOREN_ID FROM TABLE_B)返回的都是空集，查不到任何记录。办法是排除掉N... 阅读全文