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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

Functions

  • Determine whether the given data type dt is a Date or Timestamp.
  • Determine whether the given data type dt is a Decimal.
  • Determine whether the given data type ‘dt’ is a Interval.
  • Determine whether the given data type dt is Null.
  • Determine whether the given data type dt represents numeric values.
  • Determine whether the given data type dt represents signed numeric values.
  • Determine whether the given data type dt is a Timestamp.
  • Determine whether the given data type dt is a Utf8 or LargeUtf8.