CAST, ::

Converts a value from one data type to another. :: is an alias for CAST.

See also: TRY_CAST

Syntax

CAST( <expr> AS <data_type> )

<expr>::<data_type>

Examples

SELECT CAST(1 AS VARCHAR), 1::VARCHAR;

┌───────────────────────────────┐
│ cast(1 as string) │ 1::string │
├───────────────────┼───────────┤
│ 1                 │ 1         │
└───────────────────────────────┘

Cast String to Variant and Cast Variant to Map<String, Variant>

select '{"k1":"v1","k2":"v2"}'::Variant a, a::Map(String, String) b, b::Variant = a;
┌──────────────────────┬──────────────────────┬────────────────┐
│ a                    │ b                    │ b::VARIANT = a │
├──────────────────────┼──────────────────────┼────────────────┤
│ {"k1":"v1","k2":"v2"}│ {'k1':'v1','k2':'v2'}│ 1              │
└──────────────────────┴──────────────────────┴────────────────┘