Question

我想从“主题”行转换此输出...

SMARTBASE/N0184/1/MOISTURE/value
SMARTBASE/N0184/1/MOISTURE/unit
SMARTBASE/N0184/1/MOISTURE/timestamp
SMARTBASE/N0184/1/CONDUCTIVITY/value
SMARTBASE/N0184/1/CONDUCTIVITY/unit
SMARTBASE/N0184/1/CONDUCTIVITY/timestamp

到新表，如：

第一行：主题（行）的值，第二行：值（行）（mqtt-topics的值）

但这是500 ++的传感器... SMARTBASE并不总是SMARTBASE，因此regexp _...不是一个好主意...最后应将其保存为视图。

那有可能吗？我不知道如何实现它或如何开始。要转换表中的一行，我可以使用数据透视功能，但其余的我不知道。

我的主要问题：如何访问主题的各个值？

Answer 1

使用REGEXP_SUBSTR获取topic列的子字符串组件，然后使用PIVOT：

Oracle设置：

CREATE TABLE table_name ( topic, value ) AS 
SELECT 'SMARTBASE/N0184/1/MOISTURE/value',         '0.414' FROM DUAL UNION ALL
SELECT 'SMARTBASE/N0184/1/MOISTURE/unit',          'Raw VWC' FROM DUAL UNION ALL
SELECT 'SMARTBASE/N0184/1/MOISTURE/timestamp',     '2019-01-01T00:00:00.000' FROM DUAL UNION ALL
SELECT 'SMARTBASE/N0184/1/CONDUCTIVITY/value',     '0.529' FROM DUAL UNION ALL
SELECT 'SMARTBASE/N0184/1/CONDUCTIVITY/unit',      'mS/cm' FROM DUAL UNION ALL
SELECT 'SMARTBASE/N0184/1/CONDUCTIVITY/timestamp', '2019-01-01T00:00:00.000' FROM DUAL;

查询：

SELECT SENSOR_TYPE,
       SENSOR,
       TO_NUMBER( moisture_value ) AS moisture_value,
       moisture_unit,
       TO_TIMESTAMP( moisture_timestamp, 'YYYY-MM-DD"T"HH24:MI:SS.FF3' ) AS moisture_timestamp,
       TO_NUMBER( conductivity_value ) AS conductivity_value,
       conductivity_unit,
       TO_TIMESTAMP( conductivity_timestamp, 'YYYY-MM-DD"T"HH24:MI:SS.FF3' ) AS conductivity_timestamp
FROM   (
  SELECT REGEXP_SUBSTR( topic, '[^/]+', 1, 1 ) AS sensor_type,
         REGEXP_SUBSTR( topic, '[^/]+', 1, 2 ) AS sensor,
         REGEXP_SUBSTR( topic, '[^/]+', 1, 4 ) AS measurement_name,
         REGEXP_SUBSTR( topic, '[^/]+', 1, 5 ) AS measurement_metadata_type,
         value
  FROM   table_name
)
PIVOT(
  MAX( value )
  FOR ( measurement_name, measurement_metadata_type )
  IN  (
    ( 'MOISTURE', 'value'     ) AS MOISTURE_value,
    ( 'MOISTURE', 'unit'      ) AS MOISTURE_unit,
    ( 'MOISTURE', 'timestamp' ) AS MOISTURE_timestamp,
    ( 'CONDUCTIVITY', 'value'     ) AS CONDUCTIVITY_value,
    ( 'CONDUCTIVITY', 'unit'      ) AS CONDUCTIVITY_unit,
    ( 'CONDUCTIVITY', 'timestamp' ) AS CONDUCTIVITY_timestamp
  )
)

输出：

SENSOR_TYPE | SENSOR | MOISTURE_VALUE | MOISTURE_UNIT | MOISTURE_TIMESTAMP              | CONDUCTIVITY_VALUE | CONDUCTIVITY_UNIT | CONDUCTIVITY_TIMESTAMP         
:---------- | :----- | -------------: | :------------ | :------------------------------ | -----------------: | :---------------- | :------------------------------
SMARTBASE   | N0184  |           .414 | Raw VWC       | 01-JAN-19 12.00.00.000000000 AM |               .529 | mS/cm             | 01-JAN-19 12.00.00.000000000 AM

db <>提琴here

将一些子字符串从多行转换为新表

1 个答案: