MISSING_AGGREGATION 错误类

SQLSTATE:42803

非聚合表达式 <expression> 基于不参与 GROUP BY 子句的列。

将列或表达式添加到 GROUP BY、聚合表达式,或者在不关心返回组中哪些值时使用 <expressionAnyValue>

参数

  • expression:SELECT 列表中的非聚合、非分组表达式。
  • expressionAnyValueexpression 包装在 any_value() 聚合函数中。

说明

在包含 GROUP BY 子句的查询的上下文中,SELECT 列表中的局部列引用必须是:

  • 用作聚合函数的参数,或
  • GROUP BY 子句中的表达式匹配的表达式的一部分。

局部列引用是已在查询的 FROM 子句中解析为表引用的列。

换言之:列引用必须是分组键的一部分,或者必须是聚合的一部分。

Azure Databricks 会尽力而为匹配表达式:例如,它将 SELECT c1 + 5 FROM T GROUP BY 5 + c1 识别为匹配的表达式。 但 SELECT c1 FROM T GROUP BY c1 + 5 不是匹配项。

缓解操作

错误的缓解方法取决于具体原因:

  • 是否缺少分组列?

    expression 或将 expression 的相关子表达式添加到 GROUP BY 子句。

  • GROUP BY 表达式的列引用部分是否不同于 epression

    匹配 SELECT 列表中的表达式或简化 GROUP BY 表达式。

  • 是否缺少聚合?

    使用聚合函数包装列引用。 如果只需要组中的代表性值,则可以使用 any_value(epression)

示例

-- Sample data
> CREATE OR REPLACE TEMPORARY VIEW tasks(name, firstname, task, cost) AS
   VALUES ('Smith'  , 'Sam'   , 'UNPIVOT', 10),
          ('Smith'  , 'Sam'   , 'LATERAL',  5),
          ('Shuster', 'Sally' , 'DELETE' ,  7),
          ('Shuster', 'Sally' , 'GRANT'  ,  8);

-- `name` and `firstname` are part of the group by coumns, but incomplete
> SELECT name, firstname, sum(cost) FROM tasks GROUP BY firstname || ' ' || name;
 [MISSING_AGGREGATION] The expression "name" is neither present in the group by, nor is it an aggregate function.

-- Match the GROUP BY expression
> SELECT firstname || ' ' || name, sum(cost) FROM tasks GROUP BY firstname || ' ' || name;
 Sam Smith      15
 Sally Shuster  15

-- Break up the GROUP BY expression
> SELECT firstname, name, sum(cost) FROM tasks GROUP BY firstname, name;
 Sam    Smith   15
 Sally  Shuster 15

-- Missing grouping column
> SELECT name, firstname, sum(cost) FROM tasks GROUP BY name;
 [MISSING_AGGREGATION] The expression "firstname" is neither present in the group by, nor is it an aggregate function.

-- Add the grouping column
> SELECT firstname, name, sum(cost) FROM tasks GROUP BY firstname, name;
 Sam    Smith   15
 Sally  Shuster 15

-- Missing aggregate
> SELECT firstname, name, sum(cost), task FROM tasks GROUP BY firstname, name;
 [MISSING_AGGREGATION] The expression "task" is neither present in the group by, nor is it an aggregate function.

-- Add an aggregate
> SELECT firstname, name, sum(cost), array_agg(task) FROM tasks GROUP BY firstname, name;
 Sam    Smith   15  ["UNPIVOT","LATERAL"]
 Sally  Shuster 15  ["DELETE","GRANT"]

-- Return any task
> SELECT firstname, name, sum(cost), any_value(task) FROM tasks GROUP BY firstname, name;
 Sam    Smith   15  LATERAL
 Sally  Shuster 15  DELETE