I tried to make a research but just from prefixe.
Eg. when I search 10542, 110542 shouldn't be there, just 105428001.
The string :
110542004
105428001
I tried
LEFT(INV.INV_CD,5) LIKE '%".$option3."%'";
and
SUBSTRING(INV.INV_CD,1,5) LIKE '%".$option3."%'";
Both result are the same.