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Editorial Team
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Asked: 2026-05-16T02:56:04+00:00

I have some data that needs to be validated, and while I have found

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I have some data that needs to be validated, and while I have found a quick formula that works in excel I would like to find some SQL that would do the same so I can use it in my database as a check now and then.

The data is simply this:

ACACIA ST (KLN) | 1073 | 1149 | FAIL! | 76
ACACIA ST (KLN) | 1073 | 1151 | FAIL! | 78
ACACIA ST (KLN) | 1150 | 1332 | FAIL! | 182
ACACIA ST (KLN) | 1151 | 1332 | FAIL! | 181
ACACIA ST (KLN) | 1606 | 2079 |  | 473
ACTIVITY ST (WRK) | 6 | 215 | WIN! | 209
ACTIVITY ST (WRK) | 215 | 227 | WIN! | 12
ACTIVITY ST (WRK) | 227 | 423 | WIN! | 196
ACTIVITY ST (WRK) | 423 | 549 | WIN! | 126
ACTIVITY ST (WRK) | 549 | 600 |  | 51
ADRIENNE CT (WMN) | 5 | 107 | WIN! | 102
ADRIENNE CT (WMN) | 107 | 122 |  | 15
AERODROME RD (LYB) | 0 | 140 | WIN! | 140
AERODROME RD (LYB) | 140 | 428 | WIN! | 288
AERODROME RD (LYB) | 428 | 716 | WIN! | 288
AERODROME RD (LYB) | 716 | 998 | WIN! | 282
AERODROME RD (LYB) | 998 | 1280 | WIN! | 282
AERODROME RD (LYB) | 1280 | 1566 | WIN! | 286
AERODROME RD (LYB) | 1566 | 1851 | WIN! | 285
AERODROME RD (LYB) | 1851 | 2136 | WIN! | 285
AERODROME RD (LYB) | 2136 | 2421 |  | 285

Well there is a lot more data then that, ~11000+ rows of it.

Now the idea is that each road segment (the first column) has a start and end chainage (second and third column) and a length (last column), the end chainage should be the start chainage of the next segment, provided the road segment name is the same (sorted by start chainage of course). You can see that because the first rows end chainage doesn’t equal the start of the next it fails.

My bad attempt at pseudocode:

If EndChainage != NextStartChainge Where RoadSegment = NextRoadSegment Error

What I need to be able to do select all the road segments which don’t follow the rule of end chainage = start chainage of next.

So the outout from the above table would be: 

ACACIA ST (KLN) | 1073 | 1149 | FAIL! | 76
ACACIA ST (KLN) | 1073 | 1151 | FAIL! | 78
ACACIA ST (KLN) | 1150 | 1332 | FAIL! | 182
ACACIA ST (KLN) | 1151 | 1332 | FAIL! | 181

Hope that makes sense. I attempted it but just could seem to get it to work, and my SQL skills are a bit lacking.

EDIT: I can use both SQL Server and PostgreSQL.

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1 Answer

  1. Editorial Team

    Assuming that there won’t be duplicate rows, the following should be a reasonably DB-agnostic solution:

    select street, startno, endno, 
case  (select coalesce(min(s2.startno),-1) from stackchallenge s2 
       where s1.street = s2.street and 
             s1.startno <= s2.startno and 
             s1.endno < s2.endno)
    when -1 then ' '
    when endno then 'WIN!'
    else 'FAIL!'
end as validated,
length
from stackchallenge s1 order by 1,2,3
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