[英]Using Case Statements As a Pivot - DB2 SQL
我想要一份汽車運輸車清單,拖車設備數量列在不同的欄目中。 我使用case語句對不同的設備類型進行分類,但是我得到了多次返回,而不是每個運營商看到一次返回。
我試過ROW OVER()並得到相同的結果。
SELECT C.ECP_CARRIER_IDENT_ID AS ECP_ID, C.CARRIER_NM, C.MC_NB, C.DOT_NB,
(CASE WHEN E.EQUIPMENT_TYPE_CD = 'TR' THEN E.EQUIPMENT_CT END) AS TRACTORS,
(CASE WHEN E.EQUIPMENT_TYPE_CD = 'SV' THEN E.EQUIPMENT_CT END) AS VAN_TRLS,
(CASE WHEN E.EQUIPMENT_TYPE_CD = 'FT' THEN E.EQUIPMENT_CT END) AS FLATBEDS
FROM ECP_CARRIER C
JOIN ECP_CARRIER_EQUIPMENT E ON C.ECP_CARRIER_IDENT_ID = E.ECP_CARRIER_ID
WHERE CERTIFIED_FG = 1
GROUP BY C.ECP_CARRIER_IDENT_ID, C.CARRIER_NM, C.MC_NB, C.DOT_NB,
E.EQUIPMENT_TYPE_CD, E.EQUIPMENT_CT
我希望一切都在一排,但這是我得到的結果
ECP_NB CARRIER_NM MC_NB DOT_NB TRACTORS VAN_TRLS FLATBEDS
1234 Bob's Trucking 606066 66 10
1234 Bob's Trucking 606066 66 12
使用聚合函數並group by
以下方式修復group by
:
SELECT C.ECP_CARRIER_IDENT_ID AS ECP_ID, C.CARRIER_NM, C.MC_NB, C.DOT_NB,
MAX(CASE WHEN E.EQUIPMENT_TYPE_CD = 'TR' THEN E.EQUIPMENT_CT END) AS TRACTORS,
MAX(CASE WHEN E.EQUIPMENT_TYPE_CD = 'SV' THEN E.EQUIPMENT_CT END) AS VAN_TRLS,
MAX(CASE WHEN E.EQUIPMENT_TYPE_CD = 'FT' THEN E.EQUIPMENT_CT END) AS FLATBEDS
FROM ECP_CARRIER C JOIN
ECP_CARRIER_EQUIPMENT E
ON C.ECP_CARRIER_IDENT_ID = E.ECP_CARRIER_ID
WHERE CERTIFIED_FG = 1
GROUP BY C.ECP_CARRIER_IDENT_ID, C.CARRIER_NM, C.MC_NB, C.DOT_NB;
GROUP BY
的鍵組合應定義結果集中所需的每一行。 您不需要E.EQUIPMENT_TYPE_CD
(例如)的單獨行,因此它不應該在GROUP BY
。
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