根据同一个表中另一个字段的值获取Mysql编号字段的净值

Posted 2021-04-17

我使用以下查询来获取表格中数字（金额）字段的净值。净值基于称为事务类型的字段的类型进行计算。任何人都可以通过建议有任何方法来简化我的下面的查询。

    select (select sum(jvm_txn_amount) from jvm_transactions
           where  jvm_txn_mode = 'CASH' and 
           jvm_txn_type = 'Receipt' and 
           jvm_txn_mnt_stat = 'A') - 
           (select sum(jvm_txn_amount) from   jvm_transactions
           where  jvm_txn_mode = 'CASH' and 
           jvm_txn_type = 'Payment' and 
           jvm_txn_mnt_stat = 'A')as net_balance
    from   dual

答案

可能从jvm_txn_type分组开始：

SELECT SUM(IF(x.type='Receipt', s, 0)) - 
       SUM(IF(x.type='Payment', s, 0)) AS net_balance FROM 
       (  SELECT jvm_txn_type type,  SUM(jvm_txn_amount) s
            FROM jvm_transactions
           WHERE jvm_txn_mode = 'CASH'
             AND jvm_txn_mnt_stat = 'A'
        GROUP BY jvm_txn_type
       ) x

它更紧凑，重复性更低，应该使它更通用，更易于维护。