Teradata - 无效的选择表达式列表

Question

尝试对 teradata 进行选择查询，但收到此消息错误：

语法错误：选择表达式列表无效

我无法修复它。我怎样才能正确地制定查询？

   SELECT BILS01_GRADO, BILS01_CODICE_COM, BILS01_PROT, BILS01_PROG_OGG_IMP,BILS01_PROG_REC,
CASE WHEN BILS01_DATA_PRES_ISTSOSP<TO_DATE('9999-12-31','YYYY-MM-DD') AND BILS01_CTR_IST_SOSP=0 THEN BILS01_DATA_PRES_ISTSOSP
    WHEN BILS01_DATA_PRES_ISTSOSP=TO_DATE('9999-12-31','YYYY-MM-DD') AND BILS01_CTR_IST_SOSP>0 THEN DATA_CONTROVERSIA2
    WHEN BILS01_DATA_PRES_ISTSOSP=TO_DATE('9999-12-31','YYYY-MM-DD') AND BILS01_CTR_IST_SOSP=0 THEN TO_DATE('9999-12-31','YYYY-MM-DD')
    WHEN BILS01_DATA_PRES_ISTSOSP<
            (
            CASE WHEN
                (
                CASE    WHEN BILS01_DATA_SPED<to_date('9999-12-31','YYYY-MM-DD') THEN BILS01_DATA_SPED
                            WHEN BILS01_DATA_SPED=to_date('9999-12-31','YYYY-MM-DD') OR BILS01_DATA_RIC<to_date('9999-12-31','YYYY-MM-DD')THEN BILS01_DATA_RIC
                            WHEN  BILS01_DATA_ACQ<to_date('9999-12-31','YYYY-MM-DD') THEN BILS01_DATA_ACQ ELSE BILS01_DATA_PROT END AS DATA_CONTROVERSIA
                )
            <TO_DATE('1972-01-01','YYYY-MM-DD') THEN TO_DATE('1972-01-01','YYYY-MM-DD') ELSE DATA_CONTROVERSIA END AS DATA_CONTROVERSIA2
            )
        THEN BILS01_DATA_PRES_ISTSOSP ELSE DATA_CONTROVERSIA2 END AS A) AS OUT_DATA_RICH_SOSP
FROM zucow.BILS01


--GROUP BY BILS01_GRADO, BILS01_CODICE_COM, BILS01_PROT, BILS01_PROG_OGG_IMP,
--      BILS01_PROG_REC, OUT_DATA_RICH_SOSP