Data Types

In rekuiper, every column and expression has an associated data type that restricts valid values and available operations.

Supported Data Types

rekuiper supports the following data types:

Number	Data Type	Description
1	bigint	64-bit signed integer.
2	float	64-bit floating-point number.
3	string	Unicode text characters.
4	datetime	Date and time timestamp value.
5	boolean	Boolean value (true or false).
6	bytea	Binary byte array. In JSON streams, represent bytea fields as Base64-encoded strings.
7	array	Ordered list of scalar elements or nested struct values.
8	struct	Complex object consisting of named key-value attributes.

Compatibility for Comparison and Calculation

Binary operations evaluate expressions in SELECT and WHERE clauses. If an expression combines incompatible operand types, rekuiper generates a runtime error and delivers the error message to configured sinks.

Arrays and structs cannot participate directly in arithmetic or comparison operations. The following compatibility matrix specifies permitted operations between scalar types:

Left Operand	bigint	float	string	datetime	boolean
bigint	Yes	Yes	No	No	No
float	Yes	Yes	No	No	No
string	No	No	Yes	No	No
datetime	Yes	Yes	Yes (if formatted correctly)	Yes	No
boolean	No	No	No	No	Yes

The default parsing format for datetime strings is "2006-01-02T15:04:05.000Z07:00".

Null Value Handling

When an expression encounters a nil (null) operand:

1. Any comparison against nil evaluates to false.
2. Any arithmetic calculation with nil returns nil.

Type Conversions

Use the built-in cast(col, targetType) function to convert values between data types at runtime. Refer to transformation functions for usage details.