Method getFilteredTable

engine/engine.go:521–548

(table *Table, whereCommand *ast.WhereCommand, negation bool, tableName string)

}

func (engine *DbEngine) getFilteredTable(table *Table, whereCommand *ast.WhereCommand, negation bool, tableName string) (*Table, error) {
	filteredTable := getCopyOfTableWithoutRows(table)

	identifiers := whereCommand.Expression.GetIdentifiers()
	columnNames := make([]string, 0)
	for _, identifier := range identifiers {
		columnNames = append(columnNames, identifier.Token.Literal)
	}
	missingColumnName := engine.getMissingColumnName(columnNames, table)
	if missingColumnName != "" {
		return nil, &ColumnDoesNotExistError{tableName: tableName, columnName: missingColumnName}
	}

	for _, row := range MapTableToRows(table).rows {
		fulfilledFilters, err := isFulfillingFilters(row, whereCommand.Expression, whereCommand.Token.Literal)
		if err != nil {
			return nil, err
		}

		if xor(fulfilledFilters, negation) {
			for _, filteredColumn := range filteredTable.Columns {
				value := row[filteredColumn.Name]
				filteredColumn.Values = append(filteredColumn.Values, value)
			}
		}
	}
	return filteredTable, nil
}

func (engine *DbEngine) joinTables(joinCommand *ast.JoinCommand, leftTableName string) (*Table, error) {
	leftTable, exist := engine.Tables[leftTableName]