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sqldelphifirebirddelphi-7

How to find if a number can be contained in a specific range in Delphi using Firebird DB?

I have a table that contains prices for specific metalic parts with differents sizes. In order to find the right price I need to find the field where the diameter fits in the range of sizes.

It is possible that the range does not exist because of a first time order special sizes or not produced parts like very small pieces -> 1-9.

For example :

A part that has a diameter D of 37 should find the price P designated with X (because 37 is in the range of 35-49).

D(mm) :  10  | 20  |  30  |  35  |  50  |  60 |

P($)  :  45  | 46  |  70  |   X  |  89  | 100 |

How can I achieve that in my Delphi code using SQL request to a Firebird database?

Solution

  • You can select the one row using filtering and limiting to one row:

    select first 1 t.*
from t
where t.d <= 37
order by t.d desc;