How should I design my table - sql

Question

I need to create a table for operating on data, which has been provided to me like this:
col1 col2 col3
1 < 3 50%
2 < 5 50%
3 < 10 50%
1 5>RC >=3 25%
2 10>RC >=5 25%
3 20>RC >=10 25%
1 >=5 0%
2 >=10 0%
3 >=20 0%
A user of the system would be passing a number, which is present in col2 and col1 above. Let's say that the user passed 7 for col2 and 1 for col1. Business requirement is that I should return the user the following row
1 >=5 0%
Roughly speaking, it means that I checked the value in col2, and noticed that it is >=5, which my input data fits.
I was thinking of splitting col2 across two columns - one for storing the number and the other for operator. Something like this:
col1 col2 col3 col4
1 3 50% <
2 5 50% <
3 10 50% <
1 5>RC >=3 25%
2 10>RC >=5 25%
3 20>RC >=10 25%
1 5 0% >=
2 10 0% >=
3 20 0% >=
Thsi way, I will be able to write queries for addressing queries based on data in first and last three columns (though I have not running queries right now, I just did dry run). What I am not able to figure out so far is - How to address the data in rows 4,5,6? You can ignore the RC part in those rows, as I can certainly do away with it, as I am concerned with the numeric range for my queries.
I tried splitting the data for rows 4,5,6 in 2 rows each, something like:
1 3 25% >=
1 5 25% <
2 5 25% >=
2 10 25% <
3 10 25% >=
3 20 25% <
But, I see an imminent issue here, when it comes to retrieving the data. Let's say that user paased col2 = 7 AND col1 = 1. Now, I should have got only one row,that is row number 7 in the first table in my question, but I am also getting an additional row (1st row in last table, where I was splitting data for BETWEEN conditions)
Can anyone suggest me a better approach for storing this data so that my requierment can be achieved?
SQLFiddle demo: http://www.sqlfiddle.com/#!4/d2d90/7

Answer 1

I suggest, that you should just split col2 in two columns - lower and higher bound, replacing not existing bound, for example, with NULL. It will look something like this:
+----+-------+-------+----+
|col1|col2_lb|col2_hb|col3|
+----+-------+-------+----+
|1 |NULL |3 |50% |
+----+-------+-------+----+
|2 |NULL |5 |50% |
+----+-------+-------+----+
|3 |NULL |10 |50% |
+----+-------+-------+----+
|1 |3 |5 |25% |
+----+-------+-------+----+
|... |... |... |... |
+----+-------+-------+----+
|1 |5 |NULL |0% |
+----+-------+-------+----+
Using this structure, you'll be able to find needed row with simple query:
SELECT *
FROM T_TABLE t
WHERE t.col1 = :VAL1
AND NVL(t.col2_lb,:VAL2) <= :VAL2
AND NVL(t.col2_hb,:VAL2+1) > :VAL2