Understanding case statement in sas proc sql-CodePudding

I am having difficulty in understand this sas code.

select
      case    
       when DM_TURNOVER_TMP_STOCK."LIITM"n then   
        DM_TURNOVER_TMP_STOCK."LIITM"n     
      else   
        DM_TURNOVER_TMP_SALES."SDITM"n    
      end as "LIITM"n 
        
      case    
       when DM_TURNOVER_TMP_STOCK."LIMCU"n then   
        DM_TURNOVER_TMP_STOCK."LIMCU"n

normally we use sas in sql in condition statment of column but here seems to be diffrent.Please help me in understanding this in postgres term.

CodePudding user response：

Assuming this is a query from tables DM_TURNOVER_TMP_STOCK and DM_TURNOVER_TMP_SALES,
when DM_TURNOVER_TMP_STOCK.LIITM is not missing and non zero, LIITM will get the value of DM_TURNOVER_TMP_STOCK.LIITM.
Otherwise, it will get the value of DM_TURNOVER_TMP_SALES.SDITM.