3258012 - DTP failed with "SQL error with code '266' "

DTP fails with the below errors:
 
SQL error with code '266'. See the following SQL message:   Message no. RSDHA014
=> inconsistent datatype: [6970] Evaluator:type error in expression evaluator; $me      Message no. RSDHA013
=> ssage$=unable to create expressioncolumn'string(if(isnull( "ORG_PM_DATE" ), '00    Message no. RSDHA013
=> 000000', "ORG_PM_DATE" ))': Evaluator: type error in expression evaluator;[here]   Message no. RSDHA013
=> if(isnull("ORG_PM_DATE"), '00000000', "ORG_PM_DATE")(6970)  Message no. RSDHA013
Exception CX_RSDHA_MSG logged   Message no. RSBK228

• SAP BW Netweaver 7.50
• SAP BW/4HANA

"RSDHA014", "RSDHA013", "SQL error with code '266' ", "CX_RSDHA_MSG logged", "RSBK228", " inconsistent datatype" "[6970]" , "type error in expression evaluator", "RSBK228" , Output length not matching , string field, 1333, Open ODS view based on table  , KBA , BW4-DM-ADSO , DataStore Object (Advanced) , BW-WHM-DST-HAP , HANA Analysis Process , BW4-ME-ODSV , Open ODS View , Problem