Hi Tom,    Let me try to use the following example, below are two lines of record from my dataset (DATA1) Business Unit ID Currency PCS Product L04 DESC PCS Product L05 DESC PCS Product L06 DESC PCS Customer Segment L05 DESC PCS Account L06 DESC Prod No Account_Number 8 NGN Treasury Markets Treasury Mkts - Inp Treasury Mkts - Inp Other Banking BS Treasury Bills 738 115120 8 NGN Treasury Markets Treasury Mkts - Inp Treasury Mkts - Inp Other Banking BS Due from Other Banks 761 122001 Below is another dataset (mapping file). PCS Product L04 DESC PCS Product L05 DESC PCS Product L06 DESC PCS Customer Segment L05 DESC PCS Account L06 DESC Product_Number Account_Number Mapping Key BSMap Treasury Markets             Treasury Markets TMNostros Treasury Markets Treasury Mkts - Inp       624   Treasury MarketsTreasury Mkts - Inp624 TMLevel1Securities Treasury Markets Treasury Mkts - Inp       738   Treasury MarketsTreasury Mkts - Inp738 TMLevel1Securities Treasury Markets Treasury Mkts - Inp       761X   Treasury MarketsTreasury Mkts - Inp761X TMNostros Treasury Markets Treasury Mkts - Inp         122051 Treasury MarketsTreasury Mkts - Inp122051 TMNostros Treasury Markets Treasury Mkts - Inp     BS Due from Other Banks     Treasury MarketsTreasury Mkts - InpBS Due from Other Banks TMNostros Treasury Markets Treasury Mkts - Inp     BS Inv Sec - Debt Sec NGrp     Treasury MarketsTreasury Mkts - InpBS Inv Sec - Debt Sec NGrp TMLevel1Securities Treasury Markets Treasury Mkts - Inp     BS Treasury Bills     Treasury MarketsTreasury Mkts - InpBS Treasury Bills TMLevel1Securities   What I am trying to do is combine the two datasets such that my output looks like the following table. I need the last column from mapping table to be part of my DATA1.    Business Unit ID Currency PCS Product L04 DESC PCS Product L05 DESC PCS Product L06 DESC PCS Customer Segment L05 DESC PCS Account L06 DESC Prod No Account_Number RRR NGA Map 8 NGN Treasury Markets Treasury Mkts - Inp Treasury Mkts - Inp Other Banking BS Treasury Bills 738 115120 TMLevel1Securities 8 NGN Treasury Markets Treasury Mkts - Inp Treasury Mkts - Inp Other Banking BS Due from Other Banks 761 122001 TMNostros   There are records in the dataset that have data only for column "PCS PRODUCT L04 DESC", so the expectation is for them to be tagged as "TM Nostros" , but for records that have more information i.e data for other columns, they need to be tagged according to the different levels shown in mapping table.    Not sure if I have explained the problem properly, please let me know if it is unclear.     ... View more