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Syntax Compatibility Differences Between Teradata and Oracle

GaussDB(DWS) is compatible with Teradata and Oracle syntax, of which the syntax behavior is different.

Table 1 Compatibility differences

Compatibility Item

Teradata

Oracle

Data type DATE

Stores year, month, and day values.

Converts the DATE data type to the TIMESTAMP data type which stores year, month, day, hour, minute, and second values.

Empty string

An empty string is distinguished from a NULL value.

An empty string is treated as a NULL value.

Conversion from an empty string to INT

0

NULL

Automatic truncation of overlong characters

Supported (only if td_compatible_truncation is set to on)

Not supported

VARCHAR + INT calculation

Converts to NUMERIC + NUMERIC calculation.

Converts to BIGINT + INT calculation.

CASE and COALESCE expressions

Is compatible with behavior of Teradata and supports type conversion between digits and strings. For example, if input parameters for COALESCE are of INT and VARCHAR types, the parameters are resolved as VARCHAR type.

Reports error.