sql - ORACLE where 子句的案例

Question

SELECT *
FROM (
                SELECT P.PC_ID, PC.PC, P.BLOK_ID, B.BLOK, B.ID_MATERIAL, M.MATERIAL, M.NO_MATERIAL, P.START_DTTM, TO_CHAR(P.START_DTTM,'yyyy-mm-dd') DATE_PERENCANAAN
                FROM UTSG_PERENCANAAN P
                INNER JOIN UTSG_PC PC
                        ON P.PC_ID = PC.ID_PC
                INNER JOIN UTSG_BLOK B
                        ON P.BLOK_ID = B.ID_BLOK
                LEFT JOIN UTSG_MATERIAL M
                        ON B.ID_MATERIAL = M.ID_MATERIAL
                WHERE P.NO_LAMBUNG = '341'
                                AND P.LOKASI_ID = '2'
                                AND P.START_DTTM < TO_DATE('2019-01-09 23:40:52', 'yyyy-mm-dd hh24:mi:ss')
                ORDER BY P.START_DTTM DESC
)
WHERE 
    CASE
        WHEN BLOK = 'DD11'
            THEN ROWNUM <= 1
        ELSE
            THEN ROWNUM <= 2
    END

我有这样的查询，在 where 子句中总是显示的情况下

error ORA-00905: missing keyword

Answer 1

case 语句中不能有比较运算符。相反，您的 where 子句应该类似于:

WHERE 
    rownum <= CASE WHEN BLOK = 'DD11' THEN 1
                   ELSE 2
              END