使用以下MySQL表包含带有相关金额的借方或贷方“操作”,如何选择具有非零“余额”的所有CLIENT_ID？我已经尝试将表加入到自身中以计算所有借方和贷方总计,但有些东西无法正常工作.
CLIENT_ID ACTION_TYPE ACTION_AMOUNT
1 debit 1000
1 credit 100
1 credit 500
2 debit 1000
2 credit 1200
3 debit 1000
3 credit 1000
4 debit 1000
我的MySQL查询不起作用：
SELECT
client_id,SUM(t_debits) AS debits,SUM(t_credits) AS credits,SUM(t_debits)-SUM(t_credits) AS balance
FROM table_name AS t_debits
LEFT JOIN table_name AS t_credits ON t_credits.client_id=t_debits.client_id
WHERE
t_debits.action_type='debit'
AND t_credits.action_type='credit'
AND balance!=0
GROUP BY t_debits.client_id,t_credits.client_id;
我期待的结果是：
CLIENT_ID DEBITS CREDITS BALANCE
1 1000 600 400
2 1000 1200 -200
4 1000 0 1000
我不知道还有什么可以尝试的.任何帮助都会很棒.
最佳答案
DROP TABLE IF EXISTS my_table;
CREATE TABLE my_table
(transaction_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,client_id INT NOT NULL,action_type VARCHAR(12) NOT NULL,action_amount INT NOT NULL
);
INSERT INTO my_table(client_id,action_type,action_amount) VALUES
(1,'debit',1000),(1,'credit',100),500),(2,1200),(3,(4,1000);
SELECT client_id,SUM(COALESCE(CASE WHEN action_type = 'debit' THEN action_amount END,0)) total_debits,SUM(COALESCE(CASE WHEN action_type = 'credit' THEN action_amount END,0)) total_credits,0))
- SUM(COALESCE(CASE WHEN action_type = 'credit' THEN action_amount END,0)) balance
FROM my_table
GROUP
BY client_id
HAVING balance <> 0;
+-----------+--------------+---------------+---------+
| client_id | total_debits | total_credits | balance |
+-----------+--------------+---------------+---------+
| 1 | 1000 | 600 | 400 |
| 2 | 1000 | 1200 | -200 |
| 4 | 1000 | 0 | 1000 |
+-----------+--------------+---------------+---------+