以下查询现在速度非常慢，需要建议以提高性能。
SQL QUERY：
USE AGENCYDATA
SELECT reporting_period
,SUM(current_upb) as upb
,SUM(smm_prepay) as smm_prepay
,SUM(smm_default) as smm_default
,case when sum(current_upb)>0 then (1-power(1-SUM(smm_prepay)/SUM(current_upb+smm_prepay+smm_default),12))*100 else 0 end as CPR
,case when sum(current_upb)>0 then (1-power(1-SUM(smm_default)/SUM(current_upb+smm_prepay+smm_default),12))*100 else 0 end as CDR
,SUM(prior_upb-current_upb) as paydown
FROM (
SELECT p.loan_id
,reporting_period
,current_upb
,p.prior_upb
,p.zero_balance_code
,case when zero_balance_code='01' then p.prior_upb else 0 end as smm_prepay
,case when zero_balance_code in ('03','09') and repurchase_flag='N' then p.prior_upb else 0 end as smm_default
FROM Performance p
join (
SELECT p.loan_id
FROM Performance p
LEFT JOIN Acquisition a on p.gse_buyer=a.gse_buyer
and p.loan_id=a.loan_id
LEFT JOIN (
SELECT loan_id,reporting_period,dq_status
FROM Performance
) prev on prev.loan_id=p.loan_id
and prev.reporting_period=DATEADD(month,-1,p.reporting_period)
WHERE p.dq_status = '0'
and prev.dq_status not in ('0','1','2')
and p.gse_buyer='FHR'
and a.acquisition_quarter in ('2009Q1','2009Q2','2009Q3','2009Q4')
) d ON d.loan_id=p.loan_id
) b
GROUP BY
reporting_period
ORDER BY
reporting_period
绩效表的架构：
CREATE TABLE [dbo].[Performance](
[performanceId] [int] IDENTITY(1,1) NOT NULL,
[gse_buyer] [varchar](4) NULL,
[loan_id] [varchar](32) NULL,
[reporting_period] [date] NULL,
[prior_upb] [numeric](12, 2) NULL,
[current_upb] [numeric](12, 2) NULL,
[dq_status] [varchar](5) NULL,
[loan_age] [numeric](10, 0) NULL,
[remaining_months_to_maturity] [numeric](3, 0) NULL,
[current_int_rate] [numeric](14, 10) NULL,
[zero_balance_code] [varchar](2) NULL,
[zero_balance_effective_date] [date] NULL,
[modification_flag] [varchar](1) NULL,
[servicer_name_fn] [varchar](80) NULL,
[adjusted_remaining_months_to_maturity] [numeric](3, 0) NULL,
[maturity_date_fn] [date] NULL,
[repurchase_date] [date] NULL,
[repurchase_flag] [varchar](2) NULL,
[metropolitan_statistical_area_fn] [varchar](5) NULL,
[current_deferred_upb] [numeric](12, 2) NULL,
[paid_through_date] [date] NULL,
[mi_recovery] [numeric](12, 2) NULL,
[net_sales_proceeds] [varchar](30) NULL,
[non_mi_recovery] [numeric](12, 2) NULL,
[expense] [numeric](12, 2) NULL
) ON [PRIMARY]
收购表的架构：
CREATE TABLE [dbo].[Acquisition](
[acquisitionId] [int] IDENTITY(1,1) NOT NULL,
[gse_buyer] [varchar](4) NULL,
[loan_id] [varchar](20) NULL,
[channel] [varchar](1) NULL,
[seller_name] [varchar](80) NULL,
[servicer_name_fh] [varchar](80) NULL,
[acquisition_quarter] [varchar](6) NULL,
[orig_int_rate] [numeric](14, 10) NULL,
[orig_upb] [numeric](11, 2) NULL,
[orig_loan_term] [numeric](3, 0) NULL,
[orig_date] [date] NULL,
[first_payment_date] [date] NULL,
[maturity_date] [date] NULL,
[orig_ltv] [numeric](14, 10) NULL,
[orig_cltv] [numeric](14, 10) NULL,
[number_of_borrowers] [numeric](3, 0) NULL,
[dti_ratio] [numeric](14, 10) NULL,
[borrower_credit_score] [numeric](3, 0) NULL,
[first_time_home_buyer_indicator] [varchar](1) NULL,
[loan_purpose] [varchar](1) NULL,
[property_type] [varchar](2) NULL,
[number_of_units] [varchar](10) NULL,
[occupancy_status] [varchar](1) NULL,
[zipcode] [varchar](10) NULL,
[metropolitan_statistical_area] [varchar](5) NULL,
[property_state] [varchar](20) NULL,
[mortgage_insurance_percentage] [numeric](14, 10) NULL,
[product_type] [varchar](20) NULL,
[prepay_panalty_flag] [varchar](1) NULL,
[co_borrower_credit_score] [numeric](3, 0) NULL
) ON [PRIMARY]
有人可以帮助我提高此查询的效果吗？该查询已持续运行1小时，但未获得任何结果。
答案 0 :(得分：1)
我认为你的主要问题是你在没有连接的情况下再次使用同一个表。您可以尝试以下方式：
SELECT reporting_period
,SUM(current_upb) as upb
,SUM(smm_prepay) as smm_prepay
,SUM(smm_default) as smm_default
,case when sum(current_upb)>0 then (1-power(1-SUM(smm_prepay)/SUM(current_upb+smm_prepay+smm_default),12))*100 else 0 end as CPR
,case when sum(current_upb)>0 then (1-power(1-SUM(smm_default)/SUM(current_upb+smm_prepay+smm_default),12))*100 else 0 end as CDR
,SUM(prior_upb-current_upb) as paydown
FROM (
SELECT p.loan_id
,p.reporting_period
,p.current_upb
,p.prior_upb
,p.zero_balance_code
,case when p.zero_balance_code='01' then p.prior_upb else 0 end as smm_prepay
,case when p.zero_balance_code in ('03','09') and p.repurchase_flag='N' then p.prior_upb else 0 end as smm_default
FROM Performance p
join Performance prev
on prev.loan_id=p.loan_id
and prev.reporting_period=DATEADD(month,-1,p.reporting_period)
LEFT JOIN Acquisition a
on p.gse_buyer=a.gse_buyer
and p.loan_id=a.loan_id
WHERE p.dq_status = '0'
and prev.dq_status not in ('0','1','2')
and p.gse_buyer='FHR'
and a.acquisition_quarter in ('2009Q1','2009Q2','2009Q3','2009Q4')
) b
GROUP BY
reporting_period
ORDER BY
reporting_period