Excluding groups from a resultset using criteria in that resultset - sql

Question

Using SQL Server 2008.
We are given a Code, say 020286 that gives us a starting resultset.
Starting data:
Code L R G
020286 2 703 1
030383 3 6 0
031847 4 5 0
021932 7 10 0
022499 8 9 0
020068 229 310 1
020866 231 306 1
020524 232 241 0
030772 233 234 0
031787 235 236 0
031859 237 238 0
031947 239 240 0
020964 242 323 1
021215 253 342 1
030728 343 344 0
020990 345 346 0
022521 347 354 0
Now I want to exclude rows whose L is between L and R of any rows whose G=1 (in the same resultset) excepting the given Code (essentially do "L between L and R" for all G=1 except the given Code), while still keeping all G=1.
Expected results:
Code L R G
020286 2 703 1
030383 3 6 0
031847 4 5 0
021932 7 10 0
022499 8 9 0
020068 229 310 1
020866 231 306 1
020964 242 323 1
021215 253 342 1
030728 343 344 0
020990 345 346 0
022521 347 354 0
Here is a table var with starting data.
declare #t table (Code nvarchar(10),L int, R int, G int)
insert into #t (Code, L, R, G)
select '020286',2,703,1 union
select '030383',3,6,0 union
select '031847',4,5,0 union
select '021932',7,10,0 union
select '022499',8,9,0 union
select '020068',229,610,1 union
select '020866',231,396,1 union
select '020524',232,241,0 union
select '030772',233,234,0 union
select '031787',235,236,0 union
select '031859',237,238,0 union
select '031947',239,240,0 union
select '020964',242,383,1 union
select '021215',253,342,1 union
select '030728',343,344,0 union
select '020990',345,346,0 union
select '022521',347,354,0
select * from #t

Answer 1

Presumably the given code is identifyable somehow, so I'll assume there's a variable available containing it, which I'm calling #given:
DECLARE #given nvarchar(10)
SELECT #given = '020286'
First identify the L of rows where G=1 and which are not the given code:
SELECT L INTO #L FROM #t WHERE G=1 AND Code <> #given;
Now we need to join each pair of consecutive values in #L into rows in a new table which can then be used to work out which rows in #t we dont want. There's a few ways of doing this, but this one is pretty easy and simple to follow:
SELECT L as [Low], Cast(0 as int) as [High]
INTO #Pairs
FROM #L
WHERE L < (SELECT Max(L) FROM #L);
UPDATE #Pairs SET [High] = (SELECT Min(L) FROM #L WHERE L > [Low]);
Now remove the unwanted rows in #t:
DELETE t
FROM #t t CROSS JOIN #Pairs p
WHERE L > p.[Low] AND L < p.[High]
What's left should be correct:
SELECT * FROM #t ORDER BY L

Answer 2

Using your stated criteria:
Exclude rows whose L is between L and R of any rows whose G=1 (in the same resultset) excepting the given Code (essentially do "L between L and R" for all G=1 except the given Code), while still keeping all G=1:
SELECT *
FROM #t
WHERE G = 1
OR NOT(L >= (SELECT MIN(L) FROM #t WHERE G = 1 AND NOT Code = '020286')
AND L <= (SELECT MAX(R) FROM #t WHERE G = 1 AND NOT Code = '020286'))
However, your expected results do not appear to match your stated criteria. You appear to be saying (for this data set and criteria) that you want to exclude G<>1 rows with L between 229 (MIN(L) where Code <> '020286') and 610 (MAX(R) where Code <> '020286'), but these rows don't appear to match the apparent intent of your stated criteria:
CODE L R G
030728 343 344 0
020990 345 346 0
022521 347 354 0
In fact, it would appear that your criteria is actually:
Exclude rows whose L is between L and R of any previous rows whose G=1 (in the same resultset) excepting the given Code (essentially do "L between L and R" for the previous G=1 except the given Code), while still keeping all G=1:
WITH Criteria
AS (SELECT Code, L, R, G
FROM #t
WHERE G = 1)
SELECT T.Code, T.L, T.R, T.G
FROM #t AS T
INNER JOIN Criteria
ON T.L >= Criteria.L
AND T.L <= Criteria.R
AND T.G <> 1
AND Criteria.Code <> '020286'
UNION ALL
SELECT Code, L, R, G
FROM Criteria
ORDER BY 1