mysql: 运行 基于另外两行值的插入
mysql: running an insert based two other row's value
我有一个 table 列：借方、贷方、debit_balance、credit_balance 和金额。借记和贷记分别与特定帐户有关。
每次添加新行时，我都希望根据帐户之前的余额分配 debit_balance 和 credit_balance。
INSERT INTO `ledger` (`debit`, `credit`, `debit_balance`, `credit_balance`, `amount`)
VALUES ('1', '3',
(SELECT debit_balance FROM `ledger` WHERE `debit` = '1' ORDER BY `id` DESC LIMIT 0,1) + 5,
(SELECT credit_balance FROM `ledger` WHERE `credit` = '3' ORDER BY `id` DESC LIMIT 0,1) + 5,
'5')
其中借方账户为1，贷方账户为3，我要更改的金额为5。
当我 运行 查询时，mysql 给我一个 Every derived table must have its own alias 错误。
您可以使用单个 SELECT 查询来提供要插入的值。
INSERT INTO ledger (debit, credit, debit_balance, credit_balance, amount)
SELECT 1, 3, l1.debit_balance + 5, l2.credit_balance + 5, 5
FROM (SELECT MAX(id) AS debit_id FROM ledger WHERE debit = 1) AS maxd
JOIN ledger AS l1 ON l1.id = maxd.debit_id
CROSS JOIN (SELECT MAX(id) AS credit_id FROM ledger WHERE credit = 3) AS maxc
JOIN ledger AS l2 ON l2.id = maxc.credit_id
我有一个 table 列：借方、贷方、debit_balance、credit_balance 和金额。借记和贷记分别与特定帐户有关。
每次添加新行时，我都希望根据帐户之前的余额分配 debit_balance 和 credit_balance。
INSERT INTO `ledger` (`debit`, `credit`, `debit_balance`, `credit_balance`, `amount`)
VALUES ('1', '3',
(SELECT debit_balance FROM `ledger` WHERE `debit` = '1' ORDER BY `id` DESC LIMIT 0,1) + 5,
(SELECT credit_balance FROM `ledger` WHERE `credit` = '3' ORDER BY `id` DESC LIMIT 0,1) + 5,
'5')
其中借方账户为1，贷方账户为3，我要更改的金额为5。
当我 运行 查询时，mysql 给我一个 Every derived table must have its own alias 错误。
您可以使用单个 SELECT 查询来提供要插入的值。
INSERT INTO ledger (debit, credit, debit_balance, credit_balance, amount)
SELECT 1, 3, l1.debit_balance + 5, l2.credit_balance + 5, 5
FROM (SELECT MAX(id) AS debit_id FROM ledger WHERE debit = 1) AS maxd
JOIN ledger AS l1 ON l1.id = maxd.debit_id
CROSS JOIN (SELECT MAX(id) AS credit_id FROM ledger WHERE credit = 3) AS maxc
JOIN ledger AS l2 ON l2.id = maxc.credit_id