是否可以通過Hive中的恆定列進行分組？

我正在使用標準非聚合表列key1和key2上的group by運行Hive查詢。但我正在添加一個常量類型的列，根據每個表的聯合狀態的條件。是否可以通過Hive中的恆定列進行分組？

CREATE TABLE IF NOT EXISTS T_FINAL AS SELECT DISTINCT union_tbles.key1 AS key1, union_tbles.key2 AS key2, union_tbles.cnt AS cnt, union_tbles.type AS type FROM (
SELECT key1 AS key1, key2 AS key2, COUNT(val) AS cnt, 'x1' AS type FROM T_SUB1 WHERE key1 IN ('X1') GROUP BY key1, key2 
UNION ALL 
SELECT key1 AS key1, key2 AS key2, COUNT(val) AS cnt, 'x2' AS type FROM T_SUB1 WHERE key1 IN ('X2') GROUP BY key1, key2 
) union_tbles

是否可以像下面那樣將常數列類型添加爲分組列？當我試圖在group-by中添加常量列類型時，我在Hive中收到Invalid列別名錯誤。任何建議如何在Hive中實現？

CREATE TABLE IF NOT EXISTS T_FINAL AS SELECT DISTINCT union_tbles.key1 AS key1, union_tbles.key2 AS key2, union_tbles.cnt AS cnt, union_tbles.type AS type FROM (
SELECT key1 AS key1, key2 AS key2, COUNT(val) AS cnt, 'x1' AS type FROM T_SUB1 WHERE key1 IN ('X1') GROUP BY key1, key2, type 
UNION ALL 
SELECT key1 AS key1, key2 AS key2, COUNT(val) AS cnt, 'x2' AS type FROM T_SUB1 WHERE key1 IN ('X2') GROUP BY key1, key2, type 
) union_tbles

來源

2017-04-17 somnathchakrabarti

「SELECT DISTINCT」？ –

爲什麼「UNION ALL」在第一位呢？ –

我在一系列UNION上運行JOIN。我用兩種方式運行 - SELECT DISTINCT（... UNION ALL ... UNION ALL ...等）和SELECT FROM（... UNION DISTINCT ... UNION DISTINCT）。第一種方式是，就業人數爲15人，而第二種方式則爲25人。只需增加「聯盟差異」就可以大大增加就業人數。每個工作都使用9068個映射器和1009個reducer。所以它所花費的時間過高。所以我想減少工作的數量。 – somnathchakrabarti

Hive無法識別GROUP BY子句中的別名。
在任何情況下，絕對不需要按常量進行分組。
常量不需要在GROUP BY子句中進行選擇。

+---+-----+-----+-------+------------+ 
| x | _c1 | _c2 | _c3 | _c4  | 
+---+-----+-----+-------+------------+ 
| 1 | 1 | 2 | Hello | 2017-04-17 | 
+---+-----+-----+-------+------------+

來源

2017-04-17 07:25:52

是否可以通過Hive中的恆定列進行分組？

回答

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