將期初餘額添加到MySQL的第一個期末餘額行中

Question

我有一個MySQL表，我在表中顯示借方，貸方和餘額。我已經裝瞭如下定義，樣本數據和代碼到SQL Fiddle：

CREATE TABLE chequebook (
    entry_date timestamp default now() PRIMARY KEY, 
    entry_item varchar(48) NOT NULL DEFAULT '', 
    entry_amount decimal(10,2) NOT NULL DEFAULT 0.00 
) ENGINE=InnoDB DEFAULT CHARSET=utf8; 
INSERT INTO chequebook (entry_date,entry_item,entry_amount) VALUES 
('2010-01-02 12:34:00','Deposit A',215.56), 
('2010-01-02 21:44:00','Withdrawal A' ,-23.34), 
('2010-01-03 10:44:00','Withdrawal B',-150.15), 
('2010-01-03 15:44:00','Deposit B',154.67), 
('2010-01-04 18:44:00','Withdrawal C',-65.09), 
('2010-01-05 08:44:00','Withdrawal D',-74.23), 
('2010-01-06 14:44:00','Deposit C',325.12), 
('2010-01-06 20:44:00','Withdrawal E',-80.12), 
('2010-01-07 04:44:00','Withdrawal F',-110.34), 
('2010-01-07 16:44:00','Withdrawal G',-150.25), 
('2010-01-08 16:44:00','Withdrawal H',-23.90), 
('2010-01-08 21:44:00','Withdrawal I',-75.66), 
('2010-01-08 22:44:00','Deposit C',275.78), 
('2010-01-09 11:44:00','Withdrawal K',-85.99), 
('2010-01-09 21:44:00','Withdrawal J',-100.00); 

set @depos=0; 
set @total=0; 
select 
    entry_date, 
    entry_item, 
    entry_amount, 
    if(entry_amount>0, @depos:=entry_amount, @depos:=@depos+entry_amount) as depos_bal, 
    @total:=@total+entry_amount as net_bal 
from chequebook 
order by entry_date; 

我面臨的問題時，我想的期初餘額增加從PHP MYSQL查詢net_bal列。

我面臨的問題是將開盤餘額添加到第一列，然後它應該減去或加上所需字段。

例如：

|    entry_date | entry_item | entry_amount | depos_bal | net_bal | 
|---------------------------|--------------|--------------|-----------|---------| 
| January, 02 2010 12:34:00 | Deposit A |  215.56 | 5215.56 | 5215.56 | <--- 5000 is openingbalance 
| January, 02 2010 21:44:00 | Withdrawal A |  -23.34 | 5192.22 | 5192.22 | 
| January, 03 2010 10:44:00 | Withdrawal B |  -150.15 | 5042.07 | 5042.07 | 

打開平衡不同於表提取。

我該怎麼做？

Answer 1

您可以將初始本地@Total變量設置爲初始餘額。從您的SQLFiddle：

set @depos=0; 
set @total=5000; 
select 
    entry_date, 
    entry_item, 
    entry_amount, 
    if(entry_amount>0, @depos:=entry_amount, @depos:=@depos+entry_amount) as depos_bal, 
    @total:=@total+entry_amount as net_bal from chequebook 
order by entry_date; 

如果它是從一個不同的查詢來，設置變量的方式。