SQL : Tricky If Exists query needed to check overlapped values

Question

I am having a table in SQL server which stores MINIMUM_AMOUNT,MAXIMUM_AMOUNT and CURRENCY_ID Now i want to frame an SQL query which will check the new values to be inserted are already existing in the table. Ex : My table is having 2 records as follows

RANGE_ID   MINIMUM_AMOUNT     MAXIMUM_AMOUNT    CURRENCY_ID
------------------------------------------------------------
 1         3000                 9000                3
 2         12000                17000               3

Now when user inserts a new record, it should not be in between the values already available

ie : The user should not be able to enter these value pairs

  1 ) Min Amount : 4000  , Max Amount : 5000 ,Currency Id : 3
        because this range already lies in the first record (RANGE_ID 1)
  2)  Min Amount : 8000 , Max Amount : 10000,Currency d : 3
        because the minimum amount is already present in the range specified in first record (3000-9000)
  3)   Min Amount : 8000, Max Amount : 15000 , currency Id=3
       because the minimum amount is already present in one range and the maximum amount is also present in another range
  4)   Min Amount : 2500 , Max Amount : 11000 ,Currency Id=3
        because the this range overlaps with the data in first record

User should be able to enter the above range with differed Currency ID's

I am looking for a If Exists query to check this . Any help would be appreciated

Answer 1

Have a look at this

DECLARE @Table TABLE(
     RANGE_ID INT,
     MINIMUM_AMOUNT FLOAT,
     MAXIMUM_AMOUNT FLOAT,
     CURRENCY_ID INT
)

INSERT INTO @Table (RANGE_ID,MINIMUM_AMOUNT,MAXIMUM_AMOUNT,CURRENCY_ID) SELECT 1,3000,9000,3
INSERT INTO @Table (RANGE_ID,MINIMUM_AMOUNT,MAXIMUM_AMOUNT,CURRENCY_ID) SELECT 2,12000,17000,3

DECLARE @NewMin FLOAT,
     @NewMax FLOAT,
     @CurrencyID INT

SELECT  @NewMin = 4000,
     @NewMax = 5000,
     @CurrencyID = 3

SELECT  *
FROM    @Table
WHERE   CURRENCY_ID = @CurrencyID
AND  NOT (MINIMUM_AMOUNT > @NewMax OR MAXIMUM_AMOUNT < @NewMin)

This is the reverse of checking

• Full overlap
• Partial Overlap
• Internal Overlap

Answer 2

I think this will do it:

IF EXISTS
(
    SELECT *
    FROM MinMaxTable mmt
    WHERE (mmt.CURRENCY_ID = @currencyID) AND
          (@minAmount BETWEEN mmt.MINIMUM_AMOUNT AND mmt.MAXIMUM_AMOUNT) AND
          (@maxAmount BETWEEN mmt.MINIMUM_AMOUNT AND mmt.MAXIMUM_AMOUNT)
)
BEGIN
    /* New data is within an existing range. */
END
ELSE
BEGIN
    /* Partially or completely outside an existing range. */
END;

Use IF NOT EXISTS to invert the condition.

Answer 3

select 1 
from currency_ranges R
where R.CURRENCY_ID = :newCurrency
and (
(R.MINIMUM_AMOUNT <= :newMin and R.MAXIMUM_AMOUNT >= :newMin)
or (R.MINIMUM_AMOUNT <= :newMax and R.MAXIMUM_AMOUNT >= :newMax)
)

This can be used as an EXISTS statement to check for overlaps in the ranges