sql - SQL查询效率

Question

我有一个有效的查询，不确定它是否有效。

表列：

1. p_type: 可以是 STRING sell、cancelsell、bank、cancelbank
2. ID
3. 菲德
4. 单元

要执行的操作：

1. 每种流程类型的 SUM（单位）sell、cancelsell、bank、cancelbank。
2. SUM(UNIT for sell) - SUM(unit for cancelsell) , SUM(unit for bank) - SUM(unit for cancelbank)

注意：虽然我需要检查所有选择的相同值，但我也在检查每个选择中的 id 和 fid。

现有查询：

    select sell-cancelsell scount, bank-cancelbank bcount from

    (select sum(a.unit) as sell from table1 a where   
    a.p_type = 'Sell' and a.id=1 and a.fid=2 ),

    (select sum(c.unit) as cancelsell from table1  c where      
    c.p_type = 'CancelSell' and c.id=1 and c.fid=2),

    (select sum(b.unit) as bank from table1  b where     
    b.p_type = 'Bank' and b.id=1 and b.fid=2),

    (select sum(d.unit) as cancelbank from table1  d where  
    d.p_type = 'CancelBank' and d.id=1 and d.fid=2)

够好吗？如果有人可以提出一种提高效率的方法，那就太好了。

Answer 1

你可以这样做

select 
sum(Case when a.p_type = 'sell' then a.unit else null end) as sellUnit, 
sum(Case when a.p_type = 'CancelSell' then a.unit else null end) as CancelSellUnit,
sum(Case when a.p_type = 'Bank' then a.unit else null end) as BankUnit ,
sum(Case when a.p_type = 'CancelBank' then a.unit else null end) as CancelBankUnit  
from table1 a where and a.id=1 and a.fid=2 

Answer 2

试试这个：

SELECT 
        SUM(CASE WHEN P_TYPE = 'SELL' THEN UNIT END) - 
        SUM(CASE WHEN P_TYPE = 'CANCELSELL' THEN UNIT END) AS SCOUNT,
        SUM(CASE WHEN P_TYPE = 'BANK' THEN UNIT END) -
        SUM(CASE WHEN P_TYPE = 'CANCELBANK' THEN UNIT END) AS BCOUNT 
FROM    TABLE1  
WHERE   ID=1 AND FID=2 

Answer 3

select temp1.sumunit - temp2.sumunit,temp3.sumunit-temp4.sumunit from
(select p_type,sum(unit) as sumunit from table1
group by p_type) as temp1
inner join
(select p_type,sum(unit) as sumunit from table1
group by p_type) as temp2 on temp2.p_type = 'cancelsell' 
inner join
(select p_type,sum(unit) as sumunit from table1
group by p_type) as temp3 on temp3.p_type = 'bank'
inner join
(select p_type,sum(unit) as sumunit from table1
group by p_type) as temp4 on temp4.p_type='cancelbank'
where temp1.p_type='sell'
and temp1.id = 1 and temp1.fid = 2
and temp2.id = 1 and temp2.fid = 2
and temp3.id = 1 and temp3.fid = 2
and temp4.id = 1 and temp4.fid = 2