BigQuery supports UNION ALL clause in standard SQL though it doesn't support UNION clause.
BigQuery UNION ALL
The following statement shows an example of UNION ALL clause in SELECT statement.
SELECT
'A' AS Col1,
1 AS Col2
UNION ALL
SELECT
'A' AS Col1,
1 AS Col2
Output (in JSON format):
[
{
"Col1": "A",
"Col2": "1"
},
{
"Col1": "A",
"Col2": "1"
}
]
UNION DISTINCT
UNION DISTINCT is similar as UNION (without ALL) in other databases:
SELECT
'A' AS Col1,
1 AS Col2
UNION DISTINCT
SELECT
'A' AS Col1,
1 AS Col2
Output (in JSON format):
[
{
"Col1": "A",
"Col2": "1"
}
]