[英]How to construct NULL array and STRUCT in BigQuery
I have a table that has an array field.我有一个包含数组字段的表。 Here is the DDL on a temp table I made with just the field in question:
这是我用相关字段制作的临时表上的 DDL:
CREATE TABLE `project.dataset.table`
(
field ARRAY<STRUCT<value STRUCT<float_val FLOAT64, int_val INT64, string_val STRING>>>
)
How would I explicitly insert a NULL value for the field?我将如何为该字段显式插入 NULL 值?
I tried:我试过了:
SELECT
ARRAY(
SELECT AS STRUCT(
SELECT AS STRUCT(
CAST(NULL AS FLOAT64) AS float_val,
CAST(NULL AS INTEGER) AS int_val,
CAST(NULL AS STRING) AS string_val
)
)
AS field)
But I get the error: Syntax error: Parenthesized expression cannot be parsed as an expression, struct constructor, or subquery at [5:9]
但我收到错误:
Syntax error: Parenthesized expression cannot be parsed as an expression, struct constructor, or subquery at [5:9]
Try below试试下面
SELECT
ARRAY(
SELECT AS STRUCT(
SELECT AS STRUCT
CAST(NULL AS FLOAT64) AS float_val,
CAST(NULL AS INTEGER) AS int_val,
CAST(NULL AS STRING) AS string_val
) as value)
AS field
which produces below schema产生以下模式
[{
"field": [{
"value": {
"float_val": null,
"int_val": null,
"string_val": null
}
}]
}]
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