用一个实例讲解数据类型不一致引发的后果

select distinct serial_number,to_char(first_fire_date,'mm-dd-yyyy') first_fire_date,cis.installation_engineer,cis.technology,customer_name,CCS.site_nm,email_idfrom CTSV_INSTALL_SCHEDULE    cis,CTSV_RFR_RED_FLAG_REVIEW crrfr,ctst_customer_site       ccs,PRty                     pwhere CRRFR.UNIT_NUMBER =DECODE(CIS.SERIAL_NUMBER,'NON-US',CIS.ALTERNATE_SERIAL_NUMBER,CIS.SERIAL_NUMBER)AND FIRST_FIRE_STATUS <> 'RELEASE'and first_fire_date between sysdate and sysdate + 14and ccs.unit_number_id = cis.unit_numberand DECODE(p.lst_nm, NULL, p.frst_nm, p.lst_nm || ', ' || p.frst_nm) =cis.installation_engineerorder by serial_number;