Solved

MS SQL Query De-Mystified

Posted on 2009-07-13
2
187 Views
Last Modified: 2012-05-07
Can some one translate this query so it can be understood as to what it is doing?  Feel free to explain it as if you were talking to a Monkey or 3 year old


SELECT P.County_ID, P.Parcel_ID, P.Rate_ID, P.Add_ID, P.Exempt, IIf(P.UnitAssessment=-1,P.UnitAssessmentValue,IIf(P.BuildHT>=4,(P.CTaxLand*(P.Benef*0.01))+((P.CTaxBuild/P.BuildHT)*3*(P.Benef*0.01))+((P.CTaxBuild/P.BuildHT)*(P.BuildHT-3)*0.06),IIf(P.Partial_Prot=-1,IIf(P.Bldg_Incl=-1,(P.CTaxLand*(P.Wet_Perc*0.01)*0.03)+(P.CTaxBuild*0.03),P.CTaxLand*(P.Wet_Perc*0.01)*0.03),(P.CTaxLand+P.CTaxBuild)*(P.Benef*0.01)))) AS dblBenefit, BR.Bond_rate, TR.Tax_Rate, P.id, P.UnitAssessment, P.UnitAssessmentValue, TR.TaxRate_Description, P.MainCounty
FROM BondRate AS BR, MATCHEDTAXPARCELS AS P INNER JOIN TaxRate AS TR ON P.Rate_ID=TR.CharCode;
0
Comment
Question by:upgraders
2 Comments
 
LVL 15

Accepted Solution

by:
mohan_sekar earned 500 total points
ID: 24841937
Pseudo code:

if p.UnitAssessment = -1 then
   dblBenefit = p.UnitAssessmentValue
else
   if (p.BuildHT >= 4) then
        dblBenefit = (P.CTaxLand*(P.Benef*0.01))+((P.CTaxBuild/P.BuildHT)*3*(P.Benef*0.01)) +
                        ((P.CTaxBuild/P.BuildHT)*(P.BuildHT-3)*0.06)
   else
       if P.Partial_Prot = -1 then
             if P.Bldg_Incl = -1 then
                   dblBenefit = (P.CTaxLand*(P.Wet_Perc*0.01)*0.03)+(P.CTaxBuild*0.03)
             else
                   dblBenefit = P.CTaxLand*(P.Wet_Perc*0.01)*0.03)
             end if
       else
             dblBenefit = (P.CTaxLand+P.CTaxBuild)*(P.Benef*0.01)
   end if
end if
0
 
LVL 4

Expert Comment

by:j_s_kelley
ID: 24842301
The best way to understand a query is to actually format it.  Once I did that, I could see better.  Without understanding the exact nature of the query, the vast majority of it is straightforward.  It is a join where most of the fields are selected.  the field dblBenefit looks like it has some serious logic to determine it's value.  That would take an understanding of the domain to do it justice.  Also, one thing I did notice is that there are 3 tables but only two of them are joined.  BondRate is not joined with anything.  You have MatchedTaxParcels joined with Tax Rate and the result of that will be FULL OUTER JOINED with BondRate.  This is more than likely a mistake.
SELECT P.County_ID, 
	P.Parcel_ID, 
	P.Rate_ID, 
	P.Add_ID, 
	P.Exempt, 
	IIf(P.UnitAssessment=-1,P.UnitAssessmentValue,
			IIf(P.BuildHT>=4,(P.CTaxLand*(P.Benef*0.01))+((P.CTaxBuild/P.BuildHT)*3*(P.Benef*0.01))+((P.CTaxBuild/P.BuildHT)*(P.BuildHT-3)*0.06),
				IIf(P.Partial_Prot=-1,IIf(P.Bldg_Incl=-1,(P.CTaxLand*(P.Wet_Perc*0.01)*0.03)+(P.CTaxBuild*0.03),P.CTaxLand*(P.Wet_Perc*0.01)*0.03),(P.CTaxLand+P.CTaxBuild)*(P.Benef*0.01)))) AS dblBenefit, 
	BR.Bond_rate, 
	TR.Tax_Rate, 
	P.id, 
	P.UnitAssessment, 
	P.UnitAssessmentValue, 
	TR.TaxRate_Description, 
	P.MainCounty
FROM BondRate AS BR, MATCHEDTAXPARCELS AS P 
	INNER JOIN TaxRate AS TR ON P.Rate_ID=TR.CharCode

Open in new window

0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Slowly Changing Dimension Transformation component in data task flow is very useful for us to manage and control how data changes in SSIS.
For both online and offline retail, the cross-channel business is the most recent pattern in the B2C trade space.
This video shows, step by step, how to configure Oracle Heterogeneous Services via the Generic Gateway Agent in order to make a connection from an Oracle session and access a remote SQL Server database table.
Viewers will learn how to use the INSERT statement to insert data into their tables. It will also introduce the NULL statement, to show them what happens when no value is giving for any given column.

813 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

15 Experts available now in Live!

Get 1:1 Help Now