sql - 我的以下查询出现 Oracle SQL 奇怪问题

Question

我有一个名为 RULE_READOUT_VIEW 的 View ，其中包含名为“READOUTTYPE”和“CUSTOMERNUMBER”的 varchar 列。

当我运行以下计数查询时，我只得到一行作为输出。

SELECT count(1) FROM RULE_READOUT_VIEW
WHERE READOUTTYPE = '5' AND CUSTOMERNUMBER = 'NSMPF';

但是，如果运行另一个查询，我会得到不同的结果，这次计数为 11 行，这就是预期的结果。

SELECT count(1) FROM RULE_READOUT_VIEW
WHERE to_char(READOUTTYPE) = '5' AND CUSTOMERNUMBER = 'NSMPF';

我不确定为什么第一个查询不起作用，因为只有当我在列上强制使用 to_char 时，我才能得到正确的答案。我寻找答案但找不到任何令人满意的东西。有人可以解释一下为什么会出现这种行为吗？

我运行了以下查询来检查每一行的长度

SELECT READOUTTYPE, TO_CHAR(READOUTTYPE), LENGTH(READOUTTYPE), LENGTHB(READOUTTYPE) FROM teoss.RULE_READOUT_VIEW WHERE to_char(READOUTTYPE) = '5' and CUSTOMERNUMBER = 'NSMPF';

我得到 11 行作为输出，所有列的长度均为 1。

5 5 1 1
5 5 1 1
5 5 1 1
5 5 1 1
5 5 1 1
5 5 1 1
5 5 1 1
5 5 1 1
5 5 1 1
5 5 1 1
5 5 1 1

因此这些列也没有任何额外的空格。

查看DDL:

SELECT --ro.creation_date,
ro.POINT_OF_TIME_DAY                      AS pointOfReadoutDay,
ro.POINT_OF_TIME_HOUR                     AS pointOfReadoutHour,
ro.POINT_OF_TIME_MINUTE                   AS pointOfReadoutMinute,
rot.NAME                                  AS readoutType,
cp.IDENTIFICATION                         AS customerNumber,
mp.METER_POINT_NUMBER                     AS meterPointNumber,
ro.ORDER_REFERENCE                        AS readoutOrderNumber,
mtrefstat.NAME                            AS meterStatus,
mt.ADDRESS                                AS address,
mt.SERIAL_NUMBER                          AS serialNumber,
mt.UPPER_SERIAL_NUMBER                    AS upperSerialNumber,
servrefstat.NAME                          AS serverStatus,
mus.MAC                                   AS hostname,
mserv.IP_ADDRESS                          AS ipAddress ,
mt.device_id                              AS deviceID,
GET_ACCESSCONNECTION_TYPE(mus.device_id)  AS ACCESSCONNECTIONTYPE,
FUNC_LIST_OBIS_NAME(ro.order_read_out_id) AS refObisList,
mt.METER_NUMBER                           AS meterNumber
FROM ORDER_READ_OUT ro,
REF_METER_READ_OUT_TYPE rot,
COMPANY cp,
METER_POINT mp,
METER mt,
MAP_DEVICE_STATUS mtstat,
REF_STATUS mtrefstat,
DEVICE servdev,
MUS mus,
METERING_SERVER mserv,
MAP_DEVICE_STATUS servstat,
REF_STATUS servrefstat,
MAP_ORD_RD_OUT_CNTRCT_MT_PT mocm,
MAP_CONTRACT_METER_POINT mcm,
CONTRACT co
WHERE -- order readout relation has to be valid
mocm .ORDER_READ_OUT_ID         = ro.ORDER_READ_OUT_ID
AND ro.REF_METER_READ_OUT_TYPE_ID = rot.REF_METER_READ_OUT_TYPE_ID
AND ro.ACTIVATION_DATE           <= SYSTIMESTAMP
AND (ro.DEACTIVATION_DATE        IS NULL
OR ro.DEACTIVATION_DATE           > SYSTIMESTAMP)
-- contract relation has to be valid ...
AND mocm.MAP_CONTRACT_METER_POINT_ID = mcm.MAP_CONTRACT_METER_POINT_ID
AND mcm.CONTRACT_ID                  = co.CONTRACT_ID
AND co.COMPANY_ID                    = cp.COMPANY_ID
AND ((co.BEGIN                      IS NULL
AND mcm.BEGIN                       <= SYSTIMESTAMP)
OR (co.BEGIN                        <= SYSTIMESTAMP
AND mcm.BEGIN                       <= SYSTIMESTAMP
AND mcm.begin                       >= co.begin))
AND (mcm.end                        IS NULL
OR mcm.end                          >= SYSTIMESTAMP)
AND ((co.END                        IS NULL)
OR (co.END                          >= SYSTIMESTAMP
AND ((mcm.end                       IS NULL)
OR (mcm.end                         <= co.end))))
-- meter point relation has to be valid ...
AND mcm.METER_POINT_ID   = mp.METER_POINT_ID
AND mp.METER_POINT_ID    = mt.METER_POINT_ID
AND mt.DEVICE_ID         = mtstat.DEVICE_ID
AND mtstat.REF_STATUS_ID = mtrefstat.REF_STATUS_ID
AND (mtrefstat.name      = 'active'
OR mtrefstat.name        = 'toBeRemoved')
AND mtstat.STATUS_DATE   =
(SELECT MAX(mds.status_date)
FROM Map_device_status mds
WHERE mds.device_id = mtstat.DEVICE_ID
)
-- mus/metering-server relation has to be valid
AND servdev.DEVICE_ID =
(SELECT FUNC_FIND_SERVER_DEV_ID(mt.DEVICE_ID) FROM DUAL
)
AND servdev.DEVICE_ID      = mus.DEVICE_ID(+)
AND servdev.DEVICE_ID      = mserv.DEVICE_ID(+)
AND servdev.DEVICE_ID      = servstat.DEVICE_ID
AND servstat.REF_STATUS_ID = servrefstat.REF_STATUS_ID
AND (servrefstat.name      = 'active'
OR servrefstat.name        = 'toBeRemoved')
AND servstat.STATUS_DATE   =
(SELECT MAX(mds.status_date)
FROM Map_device_status mds
WHERE mds.device_id = servstat.DEVICE_ID
)
AND ro.CREATION_DATE =
(SELECT MAX(t9.CREATION_DATE)
FROM ORDER_READ_OUT t9
WHERE t9.point_of_time_day        = ro.point_of_time_day
AND t9.point_of_time_hour         = ro.point_of_time_hour
AND t9.point_of_time_minute       = ro.point_of_time_minute
AND t9.ref_meter_read_out_type_id = ro.ref_meter_read_out_type_id
AND t9.ORDER_READ_OUT_ID         IN
(SELECT t5.ORDER_READ_OUT_ID
FROM map_ord_rd_out_cntrct_mt_pt t5
WHERE t5.MAP_CONTRACT_METER_POINT_ID = mcm.MAP_CONTRACT_METER_POINT_ID
));

计划片段: 解释 SELECT count(1) FROM RULE_READOUT_VIEW WHERE READOUTTYPE = '5' AND CUSTOMERNUMBER = 'NSMPF'; 的计划

| 19 | 19按索引 ROWID 访问表| REF_METER_READ_OUT_TYPE | REF_METER_READ_OUT_TYPE | 1 | 7 | 1 |
| 20 |索引唯一扫描| UQ_REF_METER_READ_OUT_TY_NAME | 1 | | 0

    explain plan for SELECT count(1) FROM RULE_READOUT_VIEW WHERE to_char(READOUTTYPE) = '5' AND CUSTOMERNUMBER = 'NSMPF';

| 14 | 14索引快速全扫描| PK_METERREADTYPE | 1 | 7 | 1 |
| 15 | 15索引快速全扫描| UQ_REF_METER_READ_OUT_TY_NAME | 1 | 7 | 1 |

Answer 1

我怀疑您的 REF_METER_READ_OUT_TYPE.NAME 索引可能已损坏，查询结果之间的差异可以通过是否使用索引的差异来解释。

尝试删除并重新创建索引(而不是重建，因为这可能会保留任何损坏)。