Module datafusion_physical_expr::type_coercion

Type coercion rules for functions with multiple valid signatures

Coercion is performed automatically by DataFusion when the types of arguments passed to a function do not exacty match the types required by that function. 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.

Functions

coerce

Returns expressions coerced to types compatible with signature, if possible.