Method infer_data

datafusion/expr/src/logical_plan/builder.rs:297–347

(values: Vec<Vec<Expr>>)

    }

    fn infer_data(values: Vec<Vec<Expr>>) -> Result<Self> {
        let n_cols = values[0].len();
        let schema = DFSchema::empty();
        let mut fields = ValuesFields::new();

        for j in 0..n_cols {
            let mut common_type: Option<DataType> = None;
            let mut common_metadata: Option<FieldMetadata> = None;
            for (i, row) in values.iter().enumerate() {
                let value = &row[j];
                let metadata = value.metadata(&schema)?;
                if let Some(ref cm) = common_metadata {
                    if &metadata != cm {
                        return plan_err!(
                            "Inconsistent metadata across values list at row {i} column {j}. Was {:?} but found {:?}",
                            cm,
                            metadata
                        );
                    }
                } else {
                    common_metadata = Some(metadata.clone());
                }
                let data_type = value.get_type(&schema)?;
                if data_type == DataType::Null {
                    continue;
                }

                if let Some(prev_type) = common_type {
                    // get common type of each column values.
                    let data_types = vec![prev_type.clone(), data_type.clone()];
                    let Some(new_type) = type_union_resolution(&data_types) else {
                        return plan_err!(
                            "Inconsistent data type across values list at row {i} column {j}. Was {prev_type} but found {data_type}"
                        );
                    };
                    common_type = Some(new_type);
                } else {
                    common_type = Some(data_type);
                }
            }
            // assuming common_type was not set, and no error, therefore the type should be NULL
            // since the code loop skips NULL
            fields.push_with_metadata(
                common_type.unwrap_or(DataType::Null),
                true,
                common_metadata,
            );
        }

        Self::infer_inner(values, fields, &schema)
    }

    fn infer_inner(
        mut values: Vec<Vec<Expr>>,