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我正在尝试使用 Table API 中的 UNNEST 函数来展平数组。

我做错了什么还是它不是受支持的功能？这个页面虽然建议它：https ://ci.apache.org/projects/flink/flink-docs-master/dev/table/sql/queries.html

谢谢 ！

代码

Python udf

@udf(input_types=DataTypes.STRING(), result_type=DataTypes.ARRAY(DataTypes.STRING()))
def explode(s):
    return 3*[s]

t_env.register_function("explode", explode)

加工

tab = t_env.from_path('mySource').select("id, explode(dummy) as dummy_list")
t_env.register_table("temp_table", tab)
t_env.sql_query("SELECT t.item as dummy_item FROM UNNEST(select dummy_list from temp_table) AS t(item)").insert_into("mySink")

执行

t_env.execute("dummy_unnest")

错误

TableException: Cannot generate a valid execution plan for the given query: 

LogicalProject(dummy_item=[$0])
  Uncollect
    LogicalProject(EXPR$0=[org$apache$flink$table$functions$python$PythonScalarFunction$908596b4671476ee325743dba92ed6c7($1)])
      LogicalTableScan(table=[[default_catalog, default_database, mySource]])

This exception indicates that the query uses an unsupported SQL feature.
Please check the documentation for the set of currently supported SQL features.
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1 回答 1

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我认为您可以将查询更改为

select id, dummy_item from temp_table CROSS JOIN UNNEST(dummy_list) AS t (dummy_item)
于 2020-11-03T08:27:24.390 回答