clause.Eq{Column: column, Value: (*string)(nil)},
			clause.Eq{Column: column, Value: (*int)(nil)},
			clause.Eq{Column: column, Value: (*bool)(nil)},
			clause.Eq{Column: column, Value: (interface{})(nil)},
			clause.Eq{Column: column, Value: sql.NullString{String: "", Valid: false}},
		},
		Result: "`column-name` IS NULL",
	}, {
		Expressions: []clause.Expression{

					}
				} else {
					tx.Clauses(clause.Eq{Column: ref.ForeignKey.DBName, Value: ref.PrimaryValue})
				}
			}

			_, pvs := schema.GetIdentityFieldValuesMap(association.DB.Statement.Context, reflectValue, primaryFields)
			if column, values := schema.ToQueryValues(rel.JoinTable.Table, joinPrimaryKeys, pvs); len(values) > 0 {
				tx.Where(clause.IN{Column: column, Values: values})
			} else {
				return ErrPrimaryKeyRequired

					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 {

				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 {

			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) {

				}
			} 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 {

					}

					if len(selectExpr.Exprs) == 0 {
						selectExpr.Exprs = []clause.Expression{clause.Expr{SQL: "*", Vars: []interface{}{}}}
					}

					partitionBy := clause.CommaExpression{}
					for _, column := range refColumns {
						partitionBy.Exprs = append(partitionBy.Exprs, clause.Expr{SQL: "?", Vars: []interface{}{clause.Column{Name: column.Name}}})
					}

	}

	hasLogID := false
	for _, column := range columns {
		if column.Name() == "log_id" {
			hasLogID = true
			autoIncrement, ok := column.AutoIncrement()
			if !ok || !autoIncrement {
				t.Fatalf("column log_id should be auto incrementment")
			}
		}
	}

	if !hasLogID {
		t.Fatalf("failed to found column log_id")
	}
}

							set = append(set, clause.Assignment{Column: clause.Column{Name: field.DBName}, Value: now.UnixNano()})
						} else if field.AutoUpdateTime == schema.UnixMillisecond {
							set = append(set, clause.Assignment{Column: clause.Column{Name: field.DBName}, Value: now.UnixMilli()})
						} else if field.AutoUpdateTime == schema.UnixSecond {
							set = append(set, clause.Assignment{Column: clause.Column{Name: field.DBName}, Value: now.Unix()})

			} else if eq, ok := expr.(clause.Eq); ok {
				switch column := eq.Column.(type) {
				case string:
					assigns[column] = eq.Value
				case clause.Column:
					assigns[column.Name] = eq.Value
				}
			}
		}

		return tx.Model(dest).Updates(assigns)
	}

	return tx
}