Arroyo’s Scalar function implementations are based on Apache DataFusion and these docs are derived from the DataFusion function reference.

​
arrow_cast

Casts a value to a specific Arrow data type: 
arrow_cast(expression, datatype)
Arguments
  • expression: Expression to cast. Can be a constant, column, or function, and any combination of arithmetic or string operators.
  • datatype: Arrow data type name to cast to, as a string. The format is the same as that returned by [arrow_typeof]
Example 
> select arrow_cast(-5, 'Int8') as a,
  arrow_cast('foo', 'Dictionary(Int32, Utf8)') as b,
  arrow_cast('bar', 'LargeUtf8') as c,
  arrow_cast('2023-01-02T12:53:02', 'Timestamp(Microsecond, Some("+08:00"))') as d
  ;
+----+-----+-----+---------------------------+
| a  | b   | c   | d                         |
+----+-----+-----+---------------------------+
| -5 | foo | bar | 2023-01-02T12:53:02+08:00 |
+----+-----+-----+---------------------------+
1 row in set. Query took 0.001 seconds.

​
arrow_typeof

Returns the name of the underlying Arrow data type of the expression: 
arrow_typeof(expression)
Arguments
  • expression: Expression to evaluate. Can be a constant, column, or function, and any combination of arithmetic or string operators.
Example 
> select arrow_typeof('foo'), arrow_typeof(1);
+---------------------------+------------------------+
| arrow_typeof(Utf8("foo")) | arrow_typeof(Int64(1)) |
+---------------------------+------------------------+
| Utf8                      | Int64                  |
+---------------------------+------------------------+
1 row in set. Query took 0.001 seconds.