小编Tar*_*ika的帖子

delimiter $$
CREATE TRIGGER REDUCE_NOTE_COUNT
 AFTER DELETE ON iv_notes
 FOR EACH ROW  BEGIN
DECLARE supplierid int(11);
DECLARE customerid int(11);

SELECT supplierid ,customerid FROM iv_documents WHERE id=OLD.note_documentid;
SET supplierid=supplierid;
SET customerid=customerid;

IF supplierid=OLD.note_companyid THEN
    update iv_documents 
            set supplier_notes=supplier_notes-1 
            where id=OLD.note_documentid and supplier_notes>0;
END IF;
IF customerid=OLD.note_companyid THEN
    update iv_documents set customer_notes=customer_notes-1 
            where id=OLD.note_documentid 
            and customer_notes>0 ;
END IF;
END$$

分隔符;

我有如下表: -

在MySql查询的帮助下,我想得到如下结果:

date        total    read    unread
2018-01-31   8        4        4
2018-02-01   2        2        0