Query to check overlapping ranges in sql server?

Question

I have my table as

   From_Range      ToRange
   1                999
   9000             10000
   2000             5000

When I try to inse

Answer 1

This works fine for me

DECLARE @From Decimal = 2000
DECLARE @TO Decimal =5000

SELECT COUNT(ID)
FROM TABLENAME
WHERE  
(
 (
 @From BETWEEN OPEN_HRS AND (CLOSE_HRS - 1) 
 OR 
 @TO BETWEEN (OPEN_HRS + 1) AND CLOSE_HRS 
 ) 
OR
 (
 OPEN_HRS BETWEEN @From AND (@TO - 1)
 OR 
 CLOSE_HRS BETWEEN (@From + 1) AND @TO
 )
)

Answer 2

The easiest way to find an overlap is like this:

IF EXISTS (SELECT 1 FROM table WHERE @myValueLo <= ExistingRangeEnd AND @myValueHi >= ExistingRangeStart)
  -- Overlaps
ELSE
  -- Doesn't overlap

This can be shown to work if you compare the condition above against each of the bars in the diagram below:

Existing range:         |-------------------|
Overlaps:       |-------------|       |------------|
                |----------------------------------|
                           |-------------|
Not overlaps:   |-----|                       |----|

in all the overlap cases, both these tests are true:

• the start date of the existing range is always before the end date of the new range
• the end date of the existing range is after the start date of the new range

Those that don't overlap fail one or other of this test.