如何求和并在mysql的每一行中使用它

Question

hi I'm trying since yesterday to get the sum of each previous row and use it in the next row but I got the wrong results, my SQL statement is:

SELECT `RegDate`,`RegdM2`,`RegdD2`,
(@s := @s + `RegdM2`-`RegdD2`) as xresult
from tblregs2 b
cross join (select @s := 0) c
INNER JOIN tblregs1 a ON b.RegRef = a.RegRef
WHERE `RegdAccID`=32
ORDER BY RegDate

tblregs1 definition is:

CREATE TABLE `tblregs1` (
`RegID` bigint(20) NOT NULL,
`RegRef` bigint(20) NOT NULL,
`RegCode` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
`RegDate` date NOT NULL,
`RegCurr` int(11) NOT NULL,
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

INSERT INTO `tblregs1` (`RegID`, `RegRef`, `RegCode`, `RegDate`, `RegCurr`,         
`RegDetails`, `RegType`, `RegStatus`) VALUES
(1, 202010011140192, '', '2020-10-01', 1),
(2, 202010011141252, '', '2020-10-01', 1),
(3, 202010011141562, '', '2020-10-01', 1),
(4, 202010011143242, '', '2020-10-02', 0),
(5, 202010010103422, '', '2020-10-01', 1),
(6, 202010020836472, '', '2020-10-01', 0),
(7, 202010030101142, '', '2020-10-02', 0),
(8, 202010030101272, '', '2020-10-02', 0),
(9, 202010030101392, '', '2020-10-02', 0),
(10, 202010030101522, '', '2020-10-02', 0),
(11, 202010030102112, '', '2020-10-02', 0),
(12, 202010030153562, '', '2020-10-03', 1),
(14, 202010030158322, '', '2020-10-03', 1),
(15, 202010030431432, '', '2020-10-02', 0),
(16, 202010030439122, '', '2020-10-01', 1),
(17, 202010030512263, '', '2020-10-01', 1),
(18, 202010030515133, '', '2020-10-03', 2),
(19, 202010041255541, '', '2020-10-02', 1);

tblregs2 definition is:

CREATE TABLE `tblregs2` (
`RegdID` bigint(20) NOT NULL,
`RegRef` bigint(20) NOT NULL,
`RegdM1` double NOT NULL DEFAULT '0',
`RegdD1` double NOT NULL DEFAULT '0',
`RegdAccID` int(11) NOT NULL,
`RegdDetails` varchar(500) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
`RegdCurrPrice` double NOT NULL DEFAULT '0',
`RegdM2` double NOT NULL DEFAULT '0',
`RegdD2` double NOT NULL DEFAULT '0',
`RecStatus` varchar(20) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL DEFAULT 'Normal',
`RegdNo` tinyint(4) NOT NULL,
`RegdMtbkRaseed` double NOT NULL DEFAULT '0',
`RegdMtbkFark` double NOT NULL DEFAULT '0',
`RegdMtbkStatus` varchar(50) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL,
`RegdMtbkNotes` varchar(500) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

INSERT INTO `tblregs2` (`RegdID`, `RegRef`, `RegdM1`, `RegdD1`,      
`RegdAccID`, `RegdDetails`, `RegdCurrPrice`, `RegdM2`, `RegdD2`,     
`RecStatus`, `RegdNo`, `RegdMtbkRaseed`, `RegdMtbkFark`, `RegdMtbkStatus`, 
`RegdMtbkNotes`) VALUES
(1, 202010011140192, 1000, 0, 916, 'Des1', 1, 1000, 0, 'Normal', 0, 0, 0, 
NULL, NULL),
(4, 202010011141252, 0, 10000, 32, 'Des1', 1, 0, 10000, 'Normal', 2, 0, 0, 
NULL, NULL),
(13, 202010011143242, 1680, 0, 32, 'Des1', 1, 1680, 0, 'Normal', 3, -8320, 
0, 'no', 'no'),
(14, 202010011143242, 0, 1680, 15, 'Des1', 1, 0, 1680, 'Normal', 4, 0, 0, 
NULL, NULL),
(16, 202010011143242, 0, 10, 32, 'Des1', 1, 0, 10, 'Normal', 6, 0, 0, 
NULL, NULL),
(17, 202010011143242, 15, 0, 32, 'Des1', 1, 15, 0, 'Normal', 7, -8315, 0, 
'', '-8315'),
(19, 202010011143242, 450000, 0, 32, 'Des1', 1235, 364.37, 0, 'Normal', 9, 
0, 0, '', ''),
(20, 202010011143242, 0, 450000, 306, 'Des1', 1, 0, 450000, 'Normal', 10, 
0, 0, NULL, NULL),
(33, 202010020836472, 0, 0, 916, '', 0, 0, 0, 'Normal', 9, 0, 0, NULL, 
NULL),
(34, 202010020836472, 0, 0, 86, '', 0, 0, 0, 'Normal', 10, 0, 0, NULL, 
NULL),
(35, 202010030153562, 1400, 0, 32, 'Des1', 32, 1400, 0, 'Normal', 0, 
-6550.63, 0, '', '12'),
(36, 202010030153562, 0, 1400, 55, 'Des1', 55, 0, 1400, 'Normal', 0, 0, 0, 
NULL, NULL),
(38, 202010030158322, 0, 7000, 32, 'Des1', 1, 0, 7000, 'Normal', 2, 0, 0, 
NULL, NULL),
(64, 202010041255541, 0, 4500, 32, 'Des1', 1, 0, 4500, 'Normal', 2, 0, 0, 
NULL, NULL),
(65, 202010041255541, 10, 0, 33, 'Des1', 1, 10, 0, 'Normal', 3, 0, 0, 
NULL, NULL),
(66, 202010041255541, 0, 10, 45, 'Des1', 1, 0, 10, 'Normal', 4, 0, 0, 
NULL, NULL);

example of my data for the specified user is:

+-------+-----------+--------+-----------+--------+--------+
| RegID |  RegDate  | RegdID | RegdAccID | RegdM2 | RegdD2 |
+-------+-----------+--------+-----------+--------+--------+
|   2   | 10/1/2020 |    4   |     32    |    0   |  10000 |
+-------+-----------+--------+-----------+--------+--------+
|   4   | 10/2/2020 |   13   |     32    |  1680  |    0   |
+-------+-----------+--------+-----------+--------+--------+
|   4   | 10/2/2020 |   16   |     32    |    0   |   10   |
+-------+-----------+--------+-----------+--------+--------+
|   4   | 10/2/2020 |   17   |     32    |   15   |    0   |
+-------+-----------+--------+-----------+--------+--------+
|   4   | 10/2/2020 |   19   |     32    | 364.37 |    0   |
+-------+-----------+--------+-----------+--------+--------+
|   12  | 10/3/2020 |   35   |     32    |  1400  |    0   |
+-------+-----------+--------+-----------+--------+--------+
|   14  | 10/3/2020 |   38   |     32    |    0   |  7000  |
+-------+-----------+--------+-----------+--------+--------+
|   19  | 10/2/2020 |   64   |     32    |    0   |  4500  |
+-------+-----------+--------+-----------+--------+--------+

this is the result that gives me:

+-----------+--------+--------+--------+-----------+
|  RegDate  | RegdID | RegdM2 | RegdD2 |   Result  |
+-----------+--------+--------+--------+-----------+
| 10/1/2020 |    4   |    0   |  10000 |   -10000  |
+-----------+--------+--------+--------+-----------+
| 10/2/2020 |   13   |  1680  |    0   |   -8320   |
+-----------+--------+--------+--------+-----------+
| 10/2/2020 |   16   |    0   |   10   |   -8330   |
+-----------+--------+--------+--------+-----------+
| 10/2/2020 |   17   |   15   |    0   |   -8315   |
+-----------+--------+--------+--------+-----------+
| 10/2/2020 |   19   | 364.37 |    0   |  -7950.63 |
+-----------+--------+--------+--------+-----------+
| 10/2/2020 |   64   |    0   |  4500  | -18050.63 |
+-----------+--------+--------+--------+-----------+
| 10/3/2020 |   35   |  1400  |    0   |  -6550.63 |
+-----------+--------+--------+--------+-----------+
| 10/3/2020 |   38   |    0   |  7000  | -13550.63 |
+-----------+--------+--------+--------+-----------+

now I added all the requested data, hope that will help thanks, advanced

Answer 1

For 5.x version:

SELECT d.RegDate, 
       d.RegdID,
       d.RegdM2, 
       d.RegdD2, 
       CAST(@s := @s + d.RegdM2-d.RegdD2 AS DECIMAL(10,2)) AS xresult
FROM (SELECT a.RegDate,
             b.RegdM2, 
             b.RegdD2, 
             b.RegdID
       FROM tblregs2 b
       INNER JOIN tblregs1 a ON b.RegRef = a.RegRef
       WHERE b.RegdAccID=32 ) d
CROSS JOIN (SELECT @s := 0) c
ORDER BY d.RegDate, 
         d.RegdID;

For 8+ version and one account:

SELECT a.RegDate,
       b.RegdID,
       b.RegdM2, 
       b.RegdD2, 
       CAST(SUM(b.RegdM2-b.RegdD2) OVER (PARTITION BY RegdAccID 
                                         ORDER BY a.RegDate, b.RegdID) AS DECIMAL(10,2)) xresult
FROM tblregs2 b
INNER JOIN tblregs1 a ON b.RegRef = a.RegRef
WHERE b.RegdAccID=32
ORDER BY a.RegDate,
         b.RegdID;

For 8+ version and all accounts:

SELECT b.RegdAccID,
       a.RegDate,
       b.RegdID,
       b.RegdM2, 
       b.RegdD2, 
       CAST(SUM(b.RegdM2-b.RegdD2) OVER (PARTITION BY RegdAccID 
                                         ORDER BY a.RegDate, b.RegdID) AS DECIMAL(10,2)) xresult
FROM tblregs2 b
INNER JOIN tblregs1 a ON b.RegRef = a.RegRef
ORDER BY b.RegdAccID,
         a.RegDate,
         b.RegdID;

fiddle