Module datafusion_expr::type_coercion

Type coercion rules for DataFusion

Coercion is performed automatically by DataFusion when the types of arguments passed to a function or needed by operators do not exacty match the types required by that function / operator. In this case, DataFusion will attempt to coerce the arguments to types accepted by the function by inserting CAST operations.

CAST operations added by coercion are lossless and never discard information.

For example coercion from i32 -> i64 might be performed because all valid i32 values can be represented using an i64. However, i64 -> i32 is never performed as there are i64 values which can not be represented by i32 values.

Modules

• aggregates
• binary
  Coercion rules for matching argument types for binary operators
• functions
• other

Functions

• is_datetime
  Determine whether the given data type dt is a Date or Timestamp.
• is_decimal
  Determine whether the given data type dt is a Decimal.
• is_interval
  Determine whether the given data type ‘dt’ is a Interval.
• is_null
  Determine whether the given data type dt is Null.
• is_numeric
  Determine whether the given data type dt represents numeric values.
• is_signed_numeric
  Determine whether the given data type dt represents signed numeric values.
• is_timestamp
  Determine whether the given data type dt is a Timestamp.
• is_utf8_or_large_utf8
  Determine whether the given data type dt is a Utf8 or LargeUtf8.