Question

I want to compare some floating values . To do,my query is like :

SELECT * FROM pricelist WHERE START_FREQUENCY >= '(
    SELECT START_FREQUENCY
    FROM pricelist
    WHERE START_FREQUENCY BETWEEN '0.49999' AND '0.50001'
)' AND STOP_FREQUENCY <= '(
    SELECT STOP_FREQUENCY
    FROM pricelist
    WHERE STOP_FREQUENCY BETWEEN '0.59999' AND '0.60001'
)'

But in my PHP it is showing ‘Unable to execute query’ . Where I am doing wrong ? Please help

EDIT :

I have a table where there is two fields ,START_FREQUENCY and STOP_FREQUENCY . I am trying to extract the all the values with that comes within frequency range . For example say

  START_FREQUENCY STOP_FREQUENCY
1            0.4            0.9
2            0.5            1.4
3            0.8            1.9

When the user enter start frequency = 0.4 and stop frequency = 1.9 he should get results of Row1, Row2 and Row3.

Answer 1

Your inner SELECTs shouldn’t be quoted. Try this:

SELECT * FROM pricelist WHERE START_FREQUENCY >= (
    SELECT START_FREQUENCY
    FROM pricelist
    WHERE START_FREQUENCY BETWEEN 0.49999 AND 0.50001
) AND STOP_FREQUENCY <= (
    SELECT STOP_FREQUENCY
    FROM pricelist
    WHERE STOP_FREQUENCY BETWEEN 0.59999 AND 0.60001
)

I also removed the quotes around your numbers; MySQL will convert them to numbers behind your back but there’s no need to make the database guess and do more work.

Your version has this structure:

SELECT *
FROM pricelist
WHERE START_FREQUENCY >= '...'0.49999' AND '0.50001'...'
  AND STOP_FREQUENCY  <= '...'0.59999' AND '0.60001'...'

And 'string'0.49999' isn’t valid.

---

Update: Sounds like you’re just overcomplicating this. I think you just want this (using your 0.4 and 1.9):

select *
from pricelist
where START_FREQUENCY >= 0.4
  and STOP_FREQUENCY  <= 1.9