Question

Having this table, I would like to find the rows with Val fitting my Indata.

Tol field is a tolerance (varchar), that can be either an integer/float or a percentage value.

Row Val Tol   Outdata
1   24  0     A
2   24  5     B
3   24  10    C
4   32  %10   D
5   32  1     E

Indata 30 for example should match rows 3 (24+10=34) and 4 (32-10%=28.8).

Can this be done in mySQL? CREATE FUNCTION?

Answer 1

I don’t have a MySQL install to test it on, but this example is converted from Oracle sql syntax. You have to use string functions to determine if the tol is a percent and act accordingly to calculate the min and max range for that field. Then you can use a between clause.

select * 
  from (select t.*,
               case when substr(tol, 1, 1) = '%' then 
                      t.val * (1 + convert('.' + substr(tol, 2), number))
                    else 
                      t.val + convert(tol, number)
               end maxval,
               case when substr(tol, 1, 1) = '%' then 
                      t.val * (1 - convert('.' + substr(tol, 2), number))
                    else convert(t.val - tol, number)
               end minval
          from mytable
       ) t
where 30 between minval and maxval
;