Table-valued function (TVF) invocation
Applies to: Databricks SQL Databricks Runtime
Invokes a function that returns a relation or a set of rows as a table-reference.
A TVF can be a:
SQL user-defined table function.
The range table-valued function.
Any table-valued generator function, such as explode.
Applies to: Databricks SQL Databricks Runtime 12.2 LTS and above.
Note
Hive UDTF cannot be invoked as a table-reference, but must be invoked from the SELECT
or using the LATERAL VIEW clause.
Parameters
-
A table-valued function.
-
A combination of one or more values, operators, and SQL functions that results in a value.
-
An optional label to reference the function result and its columns.
Examples
-- range call with end
> SELECT * FROM range(6 + cos(3));
0
1
2
3
4
-- range call with start and end
> SELECT * FROM range(5, 10);
5
6
7
8
9
-- range call with numPartitions
> SELECT * FROM range(0, 10, 2, 200);
0
2
4
6
8
-- range call with a table alias
> SELECT * FROM range(5, 8) AS test;
5
6
7
-- Create a SQL UDTF and invoke it
> CREATE OR REPLACE FUNCTION table_func(a INT) RETURNS TABLE
RETURN SELECT a * c1 AS res FROM VALUES(1), (2), (3), (4) AS T(c1)
> SELECT * FROM table_func(5);
5
10
15
20
-- Using lateral correlation
> SELECT table_func.res FROM VALUES(10), (20) AS S(c1), LATERAL table_func(c1);
10
20
20
40
30
60
40
80
-- Scalar functions are not allowed in the FROM clause
> SELECT * FROM trim('hello ');
Error
On Databricks SQL and Databricks Runtime 12.2 LTS and above:
> SELECT * FROM explode(array(10, 20));
10
20
> SELECT * FROM inline(array(struct(1, 'a'), struct(2, 'b')));
col1 col2
---- ----
1 a
2 b
> SELECT * FROM posexplode(array(10,20));
pos col
--- ---
0 10
1 20
> SELECT * FROM stack(2, 1, 2, 3);
col0 col1
---- ----
1 2
3 null
> SELECT * FROM json_tuple('{"a":1, "b":2}', 'a', 'b');
c0 c1
--- ---
1 2
> SELECT * FROM parse_url('http://spark.apache.org/path?query=1', 'HOST');
spark.apache.org
> SELECT * FROM VALUES(1), (2) AS t1(c1), LATERAL explode (ARRAY(3,4)) AS t2(c2);
c1 c2
-- --
1 3
1 4
2 3
2 4