Data Types

tap uses Arrow, and thus the Arrow type system, for query execution. The SQL types from sqlparser-rs are mapped to Arrow data types according to the following table. This mapping occurs when defining the schema in a CREATE EXTERNAL TABLE command or when performing a SQL CAST operation.

You can see the corresponding Arrow type for any SQL expression using the arrow_typeof function. For example:

select arrow_typeof(interval '1 month');
+---------------------------------------------------------------------+
| arrow_typeof(IntervalMonthDayNano("79228162514264337593543950336")) |
+---------------------------------------------------------------------+
| Interval(MonthDayNano)                                              |
+---------------------------------------------------------------------+

You can cast a SQL expression to a specific Arrow type using the arrow_cast function For example, to cast the output of now() to a Timestamp with second precision:

select arrow_cast(now(), 'Timestamp(Second, None)');
+---------------------+
| now()               |
+---------------------+
| 2023-03-03T17:19:21 |
+---------------------+

Character Types

Numeric Types

Date/Time Types

Boolean Types

Binary Types

You can create binary literals using a hex string literal such as X'1234' to create a Binary value of two bytes, 0x12 and 0x34.

Unsupported SQL Types

Supported Arrow Types

The following types are supported by the arrow_typeof function: