Number with more than 15 characters are changing when data type is changed

[Jayshree_Tawari]

Hi!! 

I am having first table with Unique N. column. And the second table with Itemcode , Name and ID. and the combination of this three column will make an Unique N. column of first table. The problem is my ID column in second table have numbers with more than 14 char. So the moment I try to combine it or convert it to text, the actually values of column are changing. Coz of which when I try to mearge data with 1st table I am not getting the correct match values. 

Can someone help me with the solution of how to change the data type without changing the data. 

Excel Vlookup is giving the correct result but merge is not able to fetch records.

Looking for a quick help. Thanks in advance!!