UPDATE Repeated Record value in BigQuery

Question

I want to update a single value from a repeated record in BigQuery analytics events table.

I have tried going through the following link and have tried to write a query too:

UPDATE `analytics_1212191.events_2020*`
SET event_params = ARRAY(
  SELECT AS STRUCT
  b.key,
  b.value.string_value,
  b.value.float_value,
  b.value.int_value,
  b.value.double_value
  FROM UNNEST(event_params) as b

)

I want to update b.value.string_value having key = "xyz". I understand there is NO "where" clause yet for this. But the above query (even at above stage) shows the following error:

Value of type 
ARRAY<STRUCT<key STRING, string_value STRING, float_value FLOAT64, ...>> 
cannot be assigned to event_params, which has type 
ARRAY<STRUCT<key STRING, value STRUCT<string_value STRING, int_value INT64, float_value FLOAT64, ...>>> at [4:20]

---

Thanks Felipe for the answer, With the above issue fixed, I was able to use the following query for Update .

I thought I should mention the resulting query if anyone has a better idea or to help future viewers:

 UPDATE `analytics.events_test`
 SET event_params = ARRAY(
   SELECT AS STRUCT
   b.key,
   STRUCT (
     CASE WHEN b.key = "type" and b.value.string_value = "xyz" THEN "abc" ELSE b.value.string_value END,
     b.value.int_value,
     b.value.float_value,
     b.value.double_value
   ) AS value
   FROM UNNEST(event_params) as b
 )
 WHERE  event_name = "app_update" 

One pointer though:

The plan was to run it on events table and DML statements aren't supported using wildcard in partitioned tables

Answer 1

Looking at the error message, you're missing a STRUCT:

UPDATE `analytics_1212191.events_2020*`
SET event_params = ARRAY(
  SELECT AS STRUCT
  b.key,
  STRUCT (
    b.value.string_value,
    b.value.int_value,
    b.value.float_value,
    b.value.double_value
  ) AS value
  FROM UNNEST(event_params) as b
)

Answer 2

I'm with a similar issue. In my case, in clause WHERE I need specify a value of a record column, like this:

UPDATE project_name.dataset_name.table_name SET labels = ARRAY( SELECT AS STRUCT "customer", "all" FROM UNNEST(labels) as x ) WHERE labels.value = "poc" ;

But seem not possible in BigQuery. I received this message: "Cannot access field value on a value with type ARRAY<STRUCT<key STRING, value STRING>>". Any suggestion?