}

func (s Select) MergeClause(clause *Clause) {
	if s.Expression != nil {
		if s.Distinct {
			if expr, ok := s.Expression.(Expr); ok {
				expr.SQL = "DISTINCT " + expr.SQL
				clause.Expression = expr
				return
			}
		}

		clause.Expression = s.Expression
	} else {
		clause.Expression = s
	}
}

// CommaExpression represents a group of expressions separated by commas.
type CommaExpression struct {

	column := "column-name"
	results := []struct {
		Expressions  []clause.Expression
		ExpectedVars []interface{}
		Result       string
	}{{
		Expressions: []clause.Expression{
			clause.Eq{Column: column, Value: "column-value"},
		},
		ExpectedVars: []interface{}{"column-value"},
		Result:       "`column-name` = ?",
	}, {
		Expressions: []clause.Expression{
			clause.Eq{Column: column, Value: nil},

				Exprs: []clause.Expression{clause.Or(clause.Neq{Column: "name", Value: "jinzhu"}), clause.Eq{Column: clause.PrimaryColumn, Value: "1"}, clause.Gt{Column: "age", Value: 18}},
			}},
			"SELECT * FROM `users` WHERE `users`.`id` = ? OR `name` <> ? AND `age` > ?",
			[]interface{}{"1", "jinzhu", 18},
		},
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Where{

				Columns: []clause.Column{{Name: "role"}},
				Having:  []clause.Expression{clause.Eq{"role", "admin"}},
			}},
			"SELECT * FROM `users` GROUP BY `role` HAVING `role` = ?",
			[]interface{}{"admin"},
		},
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.GroupBy{
				Columns: []clause.Column{{Name: "role"}},
				Having:  []clause.Expression{clause.Eq{"role", "admin"}},
			}, clause.GroupBy{

							ON: clause.Where{
								[]clause.Expression{clause.Eq{clause.Column{Table: "profiles", Name: "email"}, clause.Column{Table: clause.CurrentTable, Name: "email"}}},
							},
						},
					},
				}, clause.From{
					Joins: []clause.Join{
						{
							Type:  clause.InnerJoin,
							Table: clause.Table{Name: "articles"},
							ON: clause.Where{

					Type:    settings["TYPE"],
					Where:   settings["WHERE"],
					Comment: settings["COMMENT"],
					Option:  settings["OPTION"],
					Fields: []IndexOption{{
						Field:      field,
						Expression: settings["EXPRESSION"],
						Sort:       settings["SORT"],
						Collate:    settings["COLLATE"],
						Length:     length,
						priority:   priority,
					}},
				})
			}
		}
	}

	err = nil

	Name5        int64  `gorm:"index:,class:FULLTEXT,comment:hello \\, world,where:age > 10"`
	Name6        int64  `gorm:"index:profile,comment:hello \\, world,where:age > 10"`
	Age          int64  `gorm:"index:profile,expression:ABS(age),option:WITH PARSER parser_name"`
	OID          int64  `gorm:"index:idx_id;index:idx_oid,unique"`
	MemberNumber string `gorm:"index:idx_id,priority:1"`
	Name7        string `gorm:"index:type"`

import (
	"database/sql"
	"database/sql/driver"
	"go/ast"
	"reflect"
)

// Expression expression interface
type Expression interface {
	Build(builder Builder)
}

// NegationExpressionBuilder negation expression builder
type NegationExpressionBuilder interface {
	NegationBuild(builder Builder)
}

// Expr raw expression
type Expr struct {
	SQL                string
	Vars               []interface{}

		if c, ok := stmt.Clauses["WHERE"]; ok {
			if where, ok := c.Expression.(clause.Where); ok && len(where.Exprs) >= 1 {
				for _, expr := range where.Exprs {
					if orCond, ok := expr.(clause.OrConditions); ok && len(orCond.Exprs) == 1 {
						where.Exprs = []clause.Expression{clause.And(where.Exprs...)}
						c.Expression = where
						stmt.Clauses["WHERE"] = c
						break
					}
				}
			}
		}

			}, clause.Select{
				Columns: []clause.Column{{Name: "name"}},
			}, clause.From{}},
			"SELECT `name` FROM `users`", nil,
		},
		{
			[]clause.Interface{clause.Select{
				Expression: clause.CommaExpression{
					Exprs: []clause.Expression{
						clause.NamedExpr{"?", []interface{}{clause.Column{Name: "id"}}},
						clause.NamedExpr{"?", []interface{}{clause.Column{Name: "name"}}},