matchedFieldCount := make(map[string]int, len(columns))
				for idx, column := range columns {
					if field := sch.LookUpField(column); field != nil && field.Readable {
						fields[idx] = field
						if count, ok := matchedFieldCount[column]; ok {
							// handle duplicate fields
							for _, selectField := range sch.Fields {
								if selectField.DBName == column && selectField.Readable {
									if count == 0 {

					clauseSelect.Columns[idx] = clause.Column{Name: name, Raw: true}
				} else if f := db.Statement.Schema.LookUpField(name); f != nil {
					clauseSelect.Columns[idx] = clause.Column{Name: f.DBName}
				} else {
					clauseSelect.Columns[idx] = clause.Column{Name: name, Raw: true}
				}
			}
		} else if db.Statement.Schema != nil && len(db.Statement.Omits) > 0 {

		},
		{
			[]clause.Interface{
				clause.Select{}, clause.From{}, clause.OrderBy{
					Columns: []clause.OrderByColumn{{Column: clause.PrimaryColumn, Desc: true}},
				}, clause.OrderBy{
					Columns: []clause.OrderByColumn{{Column: clause.Column{Name: "name"}, Reorder: true}},
				},
			},
			"SELECT * FROM `users` ORDER BY `name`", nil,
		},
		{
			[]clause.Interface{

			"SELECT * FROM `users`", nil,
		},
		{
			[]clause.Interface{clause.Select{
				Columns: []clause.Column{clause.PrimaryColumn},
			}, clause.From{}},
			"SELECT `users`.`id` FROM `users`", nil,
		},
		{
			[]clause.Interface{clause.Select{
				Columns: []clause.Column{clause.PrimaryColumn},
			}, clause.Select{
				Columns: []clause.Column{{Name: "name"}},
			}, clause.From{}},
			"SELECT `name` FROM `users`", nil,
		},
		{

 *
 * <p>The allowed row and column keys must be supplied when the table is created. The table always
 * contains a mapping for every row key / column pair. The value corresponding to a given row and
 * column is null unless another value is provided.
 *
 * <p>The table's size is constant: the product of the number of supplied row keys and the number of

   * @return the corresponding map from column keys to values
   */
  Map<C, V> row(@ParametricNullness R rowKey);

  /**
   * Returns a view of all mappings that have the given column key. For each row key / column key /
   * value mapping in the table with that column key, the returned map associates the row key with
   * the value. If no mappings in the table have the provided column key, an empty map is returned.
   *

			if stmt.Schema != nil && len(values.Columns) >= 1 {
				selectColumns, restricted := stmt.SelectAndOmitColumns(true, true)

				columns := make([]string, 0, len(values.Columns)-1)
				for _, column := range values.Columns {
					if field := stmt.Schema.LookUpField(column.Name); field != nil {
						if v, ok := selectColumns[field.DBName]; (ok && v) || (!ok && !restricted) {

			clause.Where{Exprs: []clause.Expression{
				clause.Eq{Column: clause.PrimaryColumn, Value: "1"},
				clause.Gt{Column: "age", Value: 18},
				clause.Or(clause.Neq{Column: "name", Value: "jinzhu"}),
			}},
			clause.Where{Exprs: []clause.Expression{
				clause.Or(clause.Gt{Column: "score", Value: 100}, clause.Like{Column: "name", Value: "%linus%"}),
			}},

			if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(column.Column)
			if column.Desc {
				builder.WriteString(" DESC")
			}
		}
	}
}

// MergeClause merge order by clauses
func (orderBy OrderBy) MergeClause(clause *Clause) {
	if v, ok := clause.Expression.(OrderBy); ok {
		for i := len(orderBy.Columns) - 1; i >= 0; i-- {
			if orderBy.Columns[i].Reorder {

				}
			} else {
				results[col] = result
			}
		} else {
			results[column] = result
		}
	}

	// select columns
	for _, column := range stmt.Selects {
		processColumn(column, true)
	}

	// omit columns
	for _, column := range stmt.Omits {
		processColumn(column, false)
	}

	if stmt.Schema != nil {
		for _, field := range stmt.Schema.FieldsByName {