Big query DML insert-select as into repeated tables - google-bigquery

Question

I have a table structure (table name: Recalled_transaction) as follows:
[{
"name": "STR_NBR",
"type": "STRING",
"mode": "NULLABLE"
},
{
"name": "RGSTR_NBR",
"type": "INTEGER",
"mode": "NULLABLE"
},
{
"name": "POS_TRANS_ID",
"type": "INTEGER",
"mode": "NULLABLE"
},
{
"name": "SLS_DT",
"type": "DATE",
"mode": "NULLABLE"
},
{
"name": "TRANS_ORIG_SRC",
"type": "RECORD",
"mode": "REPEATED",
"fields": [
{
"name": "POS_APPL_TYP_CD",
"type": "STRING",
"mode": "NULLABLE"
},
{
"name": "USER_ID",
"type": "STRING",
"mode": "NULLABLE"
}
]
},
{
"name": "RECALLED_TXN",
"type": "RECORD",
"mode": "REPEATED",
"fields": [
{
"name": "POS_SEQ_NBR",
"type": "STRING",
"mode": "REPEATED"
},
{
"name": "SUB_SYS_CD",
"type": "STRING",
"mode": "NULLABLE"
}
]
}
]
I would like to insert from a set of regular tables into this structure using insert-select as (DML in standard sql). Has anyone done before. Any help is appreciated.
Thanks

Answer 1

I created a table with the same schema and put together a sample query to insert into it. In your particular case, since you have two tables, you will probably need to JOIN them and then use GROUP BY.
INSERT mydataset.SampleDmlTable
(STR_NBR, RGSTR_NBR, POS_TRANS_ID, SLS_DT, TRANS_ORIG_SRC, RECALLED_TXN)
WITH T AS (
SELECT CAST(x AS STRING) AS STR_NBR,
10 - x AS RGSTR_NBR,
x AS POS_TRANS_ID,
DATE_SUB(CURRENT_DATE(), INTERVAL x DAY) AS SLS_DT,
CONCAT('foo_', CAST(x AS STRING)) AS POS_APPL_TYP_CD,
CAST(x AS STRING) AS USER_ID,
[CONCAT('bar_', CAST(x AS STRING)), 'baz'] AS POS_SEQ_NBR,
CAST(10 - x AS STRING) AS SUB_SYS_CD
FROM UNNEST([1, 1, 0, 3, 2, 2, 2]) AS x
)
SELECT
STR_NBR,
RGSTR_NBR,
POS_TRANS_ID,
SLS_DT,
ARRAY_AGG(STRUCT(POS_APPL_TYP_CD, USER_ID)) AS TRANS_ORIG_SRC,
ARRAY_AGG(STRUCT(POS_SEQ_NBR, SUB_SYS_CD)) AS RECALLED_TXN
FROM T
GROUP BY 1, 2, 3, 4;