IF NOT EXISTS (SELECT 1 FROM KSQL_USERCOLUMNS WHERE KSQL_COL_TABNAME = 'T_PUR_SRMHELP' AND KSQL_COL_NAME IN ('FNECESSARYREG')) 
 ALTER TABLE T_PUR_SRMHELP ADD (FNECESSARYREG CHAR(1) DEFAULT '0' NOT NULL );