Method infer_inner

datafusion/expr/src/logical_plan/builder.rs:349–373

(
        mut values: Vec<Vec<Expr>>,
        fields: ValuesFields,
        schema: &DFSchema,
    )

    }

    fn infer_inner(
        mut values: Vec<Vec<Expr>>,
        fields: ValuesFields,
        schema: &DFSchema,
    ) -> Result<Self> {
        let fields = fields.into_fields();
        // wrap cast if data type is not same as common type.
        for row in &mut values {
            for (j, field_type) in fields.iter().map(|f| f.data_type()).enumerate() {
                if let Expr::Literal(ScalarValue::Null, metadata) = &row[j] {
                    row[j] = Expr::Literal(
                        ScalarValue::try_from(field_type)?,
                        metadata.clone(),
                    );
                } else {
                    row[j] = std::mem::take(&mut row[j]).cast_to(field_type, schema)?;
                }
            }
        }

        let dfschema = DFSchema::from_unqualified_fields(fields, HashMap::new())?;
        let schema = DFSchemaRef::new(dfschema);

        Ok(Self::new(LogicalPlan::Values(Values { schema, values })))
    }

    /// Convert a table provider into a builder with a TableScan
    ///