DB2 Drop table if exists equivalent

Try this one:

IF EXISTS (SELECT name FROM sysibm.systables WHERE name = 'tab_name') THEN
DROP TABLE tab_name;END IF;

search on systable : if you are on as400 (power i, system i) the system table name is QSYS2.SYSTABLES else try sysibm.systables or syscat.tables (This depends on the operating system)

BEGIN    
IF EXISTS (SELECT NAME FROM QSYS2.SYSTABLES WHERE TABLE_SCHEMA = 'YOURLIBINUPPER' AND TABLE_NAME = 'YOUTABLENAMEINUPPER') THEN           
  DROP TABLE YOURLIBINUPPER.YOUTABLENAMEINUPPER;                             
END IF;                                                        
END  ; 

This is simpler and works for me:

DROP TABLE SCHEMA.TEST IF EXISTS;

The below worked for me in DB2 which queries the SYSCAT.TABLES view to check if the table exists. If yes, it prepares and executes the DROP TABLE statement.

BEGIN    
   IF EXISTS (SELECT TABNAME FROM SYSCAT.TABLES WHERE TABSCHEMA = 'SCHEMA_NAME' AND TABNAME = 'TABLE_NAME') THEN 
      PREPARE stmt FROM 'DROP TABLE SCHEMA_NAME.TABLE_NAME';
      EXECUTE stmt;
   END IF;                                                        
END