Struct functions

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

struct

Returns an Arrow struct using the specified input expressions. Fields in the returned struct use the cN naming convention. For example: c0, c1, c2, etc.

struct(expression1[, ..., expression_n])

For example, this query converts two columns a and b to a single column with a struct type of fields c0 and c1:

select * from t;
+---+---+
| a | b |
+---+---+
| 1 | 2 |
| 3 | 4 |
+---+---+

select struct(a, b) from t;
+-----------------+
| struct(t.a,t.b) |
+-----------------+
| {c0: 1, c1: 2}  |
| {c0: 3, c1: 4}  |
+-----------------+

Arguments

• expression_n: Expression to include in the output struct. Can be a constant, column, or function, and any combination of arithmetic or string operators.