TYPEOF

typeof(expr)

Function

Returns the data type of an expression. Useful for querying type information about expressions or columns, especially in dynamic SQL and type-checking scenarios.

Parameters

• expr: An expression of any type

Return Value

• string type
• Returns the name of the expression's data type
• For primitive types, returns the type name (e.g., 'int', 'string', 'boolean')
• For complex types, returns the full type definition (e.g., array<...>, map<...>, struct<...>)

Examples

SELECT typeof(true); -- Result: boolean

SELECT typeof(1); -- Result: int

SELECT typeof(1.0); -- Result: decimal(2,1)

SELECT typeof("1"); -- Result: string

SELECT typeof(array(1, 2, 3)); -- Result: array<int>

SELECT typeof(map(1, 2)); -- Result: map<int,int>

SELECT typeof(struct(1, 2, 3)); -- Result: struct<col1:int,col2:int,col3:int>

Notes

• typeof returns a type name string, not a type object
• For decimal types, the full precision information is returned, e.g., 'decimal(10,2)'
• For complex types (array, map, struct), the full nested type definition is returned
• Field names in struct types default to col1, col2, col3, etc.
• The function resolves types at compile time and does not change at runtime
• Common use cases:
  • Debugging and diagnostics
  • Generating type-related metadata
• Note: TYPEOF returns only type information and does not include NULL constraint information
• The function has minimal performance impact because type information is determined at compile time