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MERGE INTO

最后更新时间:2024-08-07 17:26:21

    说明

    支持内核:SparkSQL。
    适用表范围:原生 Iceberg 表、外部表。
    用途:行级数据更新操作,可用于替换 INSERT OVERWRITE 操作。

    语法

    MERGE INTO tablePrimary1 [ [ AS ] alias ]
    USING tablePrimary2
    ON booleanExpression
    [ WHEN MATCHED (AND matchedCond=booleanExpression)? THEN DELETE ]*
    [ WHEN MATCHED (AND matchedCond=booleanExpression)? THEN UPDATE SET assign [, assign ]* ]*
    [ WHEN NOT MATCHED (AND notMatchedCond=booleanExpression)? THEN INSERT VALUES '(' value [ , value ]*

    参数

    tablePrimary1:指定表名,支持三段式,例如:catalog.database.table。
    alias:别名。
    tablePrimary2:可以是表名,也可以是子查询。
    booleanExpression:布尔表达式。

    示例

    MERGE INTO catalog1.db2.tbl1 t
    USING catalog1.db1.tbl1
    ON t.col1 = tbl1.col1
    WHEN MATCHED AND t.col1 = 14 THEN DELETE
    
    MERGE INTO catalog1.db2.tbl1 t
    USING (SELECT col1 FROM catalog1.db1.tbl1) s
    ON t.col1 = s.col1
    WHEN MATCHED AND t.col1 = 14 THEN UPDATE SET col1 = 2
    
    
    MERGE INTO catalog1.db2.tbl1 t
    USING (SELECT col1 FROM catalog1.db1.tbl1) s
    ON t.col1 = s.col1
    WHEN MATCHED AND t.col1 = 12 THEN UPDATE SET col1 = 0
    WHEN MATCHED AND t.col1 = 13 THEN UPDATE SET col1 = 1
    WHEN MATCHED AND t.col1 = 14 THEN UPDATE SET col1 = 2
    WHEN MATCHED AND t.col1 = 15 or s.col1 = 16 THEN UPDATE SET col1 = t.col1 + 1
    WHEN MATCHED AND t.col1 not in (12, 13, 14, 15) THEN UPDATE SET col1 = 4
    WHEN NOT MATCHED AND t.col1 = 12 THEN INSERT (col1) VALUES (s.col1)
    WHEN NOT MATCHED AND t.col1 = 13 THEN INSERT (col1) VALUES (s.col1 + 1)
    WHEN NOT MATCHED AND t.col1 = 14 THEN INSERT (col1) VALUES (s.col1 + 2)
    
    
    MERGE INTO catalog1.db2.tbl1 t
    USING (SELECT col1, col2 FROM catalog1.db1.tbl1) s
    ON t.col1 = s.col1
    WHEN MATCHED AND t.col1 = fun1(s.col2) THEN DELETE
    WHEN MATCHED AND t.col1 = db2.fun1(s.col2) THEN DELETE
    WHEN MATCHED AND (t.col1 = length(s.col2) or t.col1 = catalog2.db2.fun3(s.col2)) THEN UPDATE SET col1 = 3
    WHEN NOT MATCHED AND t.col1 = 12 THEN INSERT (col1) VALUES (db2.fun2(s.col2))
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