struct function
Applies to: 
Databricks SQL Databricks Runtime
Creates a STRUCT with the specified field values.
Syntax
struct(expr1 [, ...] )
Arguments
exprN: An expression of any type.
Returns
A struct with fieldN matching the type of exprN.
If the arguments are named references, the names are used to name the field.
Otherwise, the fields are named colN, where N is the position of the field in the struct.
Examples
> SELECT struct(c1, c2, c3) FROM VALUES(1, 2, 3) AS T(c1, c2, c3);
{"c1":1,"c2":2,"c3":3}
> SELECT struct(1, 2, 3);
{"col1":1,"col2":2,"col3":3}