package exporter

import (
	"encoding/json"
	"errors"
	"fmt"
	"server/internal/schema"
	"strconv"
	"strings"
	"time"
)

type BuildRequest struct {
	MainTable  string
	Datasource string
	Fields     []string // table.field
	Filters    map[string]interface{}
}

func BuildSQL(req BuildRequest, whitelist map[string]bool) (string, []interface{}, error) {
	if req.MainTable != "order" && req.MainTable != "order_info" {
		return "", nil, errors.New("unsupported main table")
	}
	sch := schema.Get(req.Datasource, req.MainTable)
	if req.Datasource == "marketing" && req.MainTable == "order" {
		if v, ok := req.Filters["create_time_between"]; ok {
			switch t := v.(type) {
			case []interface{}:
				if len(t) != 2 {
					return "", nil, errors.New("create_time_between 需要两个时间值")
				}
			case []string:
				if len(t) != 2 {
					return "", nil, errors.New("create_time_between 需要两个时间值")
				}
			default:
				return "", nil, errors.New("create_time_between 格式错误")
			}
		} else {
			return "", nil, errors.New("缺少时间过滤：必须提供 create_time_between")
		}
	}
	cols := []string{}
	need := map[string]bool{}
	for _, tf := range req.Fields {
		// normalize YMT physical names saved previously to logical names
		if req.Datasource == "ymt" && strings.HasPrefix(tf, "order_info.") {
			tf = strings.Replace(tf, "order_info.", "order.", 1)
		}
		if whitelist != nil && !whitelist[tf] {
			continue
		}
		parts := strings.Split(tf, ".")
		if len(parts) != 2 {
			return "", nil, errors.New("invalid field format")
		}
		t, f := parts[0], parts[1]
		if req.Datasource == "marketing" && t == "order_voucher" && f == "channel_batch_no" {
			f = "channel_activity_id"
		}
		if req.Datasource == "ymt" && t == "order_voucher" && f == "channel_activity_id" {
			f = "channel_batch_no"
		}
		need[t] = true
		mt := sch.TableName(t)
		mf, _ := sch.MapField(t, f)
		if req.Datasource == "marketing" && t == "order" && req.MainTable == "order" {
			if f == "status" {
				cols = append(cols, "CASE `order`.status WHEN 0 THEN '待充值' WHEN 1 THEN '充值中' WHEN 2 THEN '已完成' WHEN 3 THEN '充值失败' WHEN 4 THEN '已取消' WHEN 5 THEN '已过期' WHEN 6 THEN '待支付' END AS `order.status`")
				continue
			}
			if f == "type" {
				cols = append(cols, "CASE `order`.type WHEN 1 THEN '直充卡密' WHEN 2 THEN '立减金' WHEN 3 THEN '红包' ELSE '' END AS `order.type`")
				continue
			}
			if f == "pay_type" {
				cols = append(cols, "CASE `order`.pay_type WHEN 1 THEN '支付宝' WHEN 5 THEN '微信' ELSE '' END AS `order.pay_type`")
				continue
			}
			if f == "pay_status" {
				cols = append(cols, "CASE `order`.pay_status WHEN 1 THEN '待支付' WHEN 2 THEN '已支付' WHEN 3 THEN '已退款' ELSE '' END AS `order.pay_status`")
				continue
			}
			if req.Datasource == "marketing" && f == "card_code" {
				cols = append(cols, "CASE WHEN LENGTH(`order`.card_code) > 10 THEN CONCAT(SUBSTRING(`order`.card_code,1,6),'****',SUBSTRING(`order`.card_code, LENGTH(`order`.card_code)-3, 4)) ELSE `order`.card_code END AS `order.card_code`")
				continue
			}
		}
		if req.Datasource == "ymt" && t == "order" {
			if f == "type" {
				cols = append(cols, "CASE `"+mt+"`.type WHEN 1 THEN '红包订单' WHEN 2 THEN '直充卡密订单' WHEN 3 THEN '立减金订单' ELSE '' END AS `order.type`")
				continue
			}
			if f == "status" {
				cols = append(cols, "CASE `"+mt+"`.status WHEN 1 THEN '待充值' WHEN 2 THEN '充值中' WHEN 3 THEN '充值成功' WHEN 4 THEN '充值失败' WHEN 5 THEN '已过期' WHEN 6 THEN '已作废' WHEN 7 THEN '已核销' WHEN 8 THEN '核销失败' WHEN 9 THEN '订单重置' WHEN 10 THEN '卡单' ELSE '' END AS `order.status`")
				continue
			}
			if f == "pay_status" {
				cols = append(cols, "CASE `"+mt+"`.pay_status WHEN 1 THEN '待支付' WHEN 2 THEN '支付中' WHEN 3 THEN '已支付' WHEN 4 THEN '取消支付' WHEN 5 THEN '退款中' WHEN 6 THEN '退款成功' ELSE '' END AS `order.pay_status`")
				continue
			}
		}
		if req.Datasource == "ymt" && t == "activity" {
			if f == "settlement_type" {
				cols = append(cols, "CASE `"+mt+"`.settlement_type WHEN 1 THEN '发放结算' WHEN 2 THEN '打开结算' WHEN 3 THEN '领用结算' WHEN 4 THEN '核销结算' ELSE '' END AS `activity.settlement_type`")
				continue
			}
		}
		if req.Datasource == "ymt" && t == "order_digit" {
			if f == "order_type" {
				cols = append(cols, "CASE `"+mt+"`.order_type WHEN 1 THEN '直充' WHEN 2 THEN '卡密' ELSE '' END AS `order_digit.order_type`")
				continue
			}
		}
		if t == "order_cash" && f == "receive_status" {
			cols = append(cols, "CASE `order_cash`.receive_status WHEN 0 THEN '待领取' WHEN 1 THEN '领取中' WHEN 2 THEN '领取成功' WHEN 3 THEN '领取失败' ELSE '' END AS `order_cash.receive_status`")
			continue
		}
		// YMT 的 order_cash 表无 is_confirm 字段，输出占位常量
		if req.Datasource == "ymt" && t == "order_cash" && f == "is_confirm" {
			cols = append(cols, "0 AS `order_cash.is_confirm`")
			continue
		}
		if t == "order_cash" && f == "channel" {
			cols = append(cols, "CASE `order_cash`.channel WHEN 1 THEN '支付宝' WHEN 2 THEN '微信' WHEN 3 THEN '云闪付' ELSE '' END AS `order_cash.channel`")
			continue
		}
		if t == "order_voucher" && f == "channel" {
			cols = append(cols, "CASE `order_voucher`.channel WHEN 1 THEN '支付宝' WHEN 2 THEN '微信' WHEN 3 THEN '云闪付' ELSE '' END AS `order_voucher.channel`")
			continue
		}
		if req.Datasource == "ymt" && t == "order_voucher" && f == "status" {
			cols = append(cols, "CASE `order_voucher`.status WHEN 1 THEN '待发放' WHEN 2 THEN '发放中' WHEN 3 THEN '发放失败' WHEN 4 THEN '待核销' WHEN 5 THEN '已核销' WHEN 6 THEN '已过期' WHEN 7 THEN '已退款' ELSE '' END AS `order_voucher.status`")
			continue
		}
		if t == "order_voucher" && f == "status" {
			cols = append(cols, "CASE `order_voucher`.status WHEN 1 THEN '可用' WHEN 2 THEN '已实扣' WHEN 3 THEN '已过期' WHEN 4 THEN '已退款' WHEN 5 THEN '领取失败' WHEN 6 THEN '发放中' WHEN 7 THEN '部分退款' WHEN 8 THEN '已退回' WHEN 9 THEN '发放失败' ELSE '' END AS `order_voucher.status`")
			continue
		}
		if t == "order_voucher" && f == "receive_mode" {
			cols = append(cols, "CASE `order_voucher`.receive_mode WHEN 1 THEN '渠道授权用户id' WHEN 2 THEN '手机号或邮箱' ELSE '' END AS `order_voucher.receive_mode`")
			continue
		}
		if t == "order_voucher" && f == "out_biz_no" {
			cols = append(cols, "'' AS `order_voucher.out_biz_no`")
			continue
		}
		// Fallback for YMT tables that are not joined in schema: voucher, voucher_batch, merchant_key_send
		if req.Datasource == "ymt" && (t == "voucher" || t == "voucher_batch" || t == "merchant_key_send") {
			cols = append(cols, "'' AS `"+t+"."+f+"`")
			continue
		}
		cols = append(cols, "`"+mt+"`."+escape(mf)+" AS `"+t+"."+f+"`")
	}
	if len(cols) == 0 {
		return "", nil, errors.New("no fields")
	}
	sb := strings.Builder{}
	baseCols := strings.Join(cols, ",")
	sb.WriteString("SELECT ")
	sb.WriteString(baseCols)
	sb.WriteString(" FROM `" + sch.TableName(req.MainTable) + "`")

	args := []interface{}{}
	where := []string{}
	// collect need from filters referencing related tables
	if _, ok := req.Filters["order_cash_cash_activity_id_eq"]; ok {
		need["order_cash"] = true
	}
	if _, ok := req.Filters["order_voucher_channel_activity_id_eq"]; ok {
		need["order_voucher"] = true
	}
	if _, ok := req.Filters["voucher_batch_channel_activity_id_eq"]; ok {
		need["voucher_batch"] = true
		need["voucher"] = true
		need["order_voucher"] = true
	}
	if _, ok := req.Filters["merchant_out_biz_no_eq"]; ok {
		need["merchant_key_send"] = true
	}

	// Handle creator_in and merchant_id_in with OR logic if both exist
	var creatorArgs []interface{}
	hasCreator := false
	if v, ok := req.Filters["creator_in"]; ok {
		switch t := v.(type) {
		case []interface{}:
			creatorArgs = t
		case []int:
			for _, x := range t {
				creatorArgs = append(creatorArgs, x)
			}
		case []string:
			for _, x := range t {
				creatorArgs = append(creatorArgs, x)
			}
		}
		if len(creatorArgs) > 0 {
			hasCreator = true
		}
	}

	var merchantArgs []interface{}
	hasMerchant := false
	if v, ok := req.Filters["merchant_id_in"]; ok {
		switch t := v.(type) {
		case []interface{}:
			merchantArgs = t
		case []int:
			for _, x := range t {
				merchantArgs = append(merchantArgs, x)
			}
		case []string:
			for _, x := range t {
				merchantArgs = append(merchantArgs, x)
			}
		}
		if len(merchantArgs) > 0 {
			hasMerchant = true
		}
	}

	// Apply the logic: if both present, use OR. Else use individual.
	if hasCreator && hasMerchant {
		cTbl, cCol, cOk := sch.FilterColumn("creator_in")
		mTbl, mCol, mOk := sch.FilterColumn("merchant_id_in")
		if cOk && mOk {
			cPh := strings.Repeat("?,", len(creatorArgs))
			cPh = strings.TrimSuffix(cPh, ",")
			mPh := strings.Repeat("?,", len(merchantArgs))
			mPh = strings.TrimSuffix(mPh, ",")
			where = append(where, fmt.Sprintf("(`%s`.%s IN (%s) OR `%s`.%s IN (%s))",
				sch.TableName(cTbl), escape(cCol), cPh,
				sch.TableName(mTbl), escape(mCol), mPh))
			args = append(args, creatorArgs...)
			args = append(args, merchantArgs...)
		} else if cOk {
			// Fallback: only creator valid (e.g. marketing system)
			ph := strings.Repeat("?,", len(creatorArgs))
			ph = strings.TrimSuffix(ph, ",")
			where = append(where, fmt.Sprintf("`%s`.%s IN (%s)", sch.TableName(cTbl), escape(cCol), ph))
			args = append(args, creatorArgs...)
		}
	} else if hasCreator {
		if tbl, col, ok := sch.FilterColumn("creator_in"); ok {
			ph := strings.Repeat("?,", len(creatorArgs))
			ph = strings.TrimSuffix(ph, ",")
			where = append(where, fmt.Sprintf("`%s`.%s IN (%s)", sch.TableName(tbl), escape(col), ph))
			args = append(args, creatorArgs...)
		}
	}

	if v, ok := req.Filters["create_time_between"]; ok {
		var arr []interface{}
		b, _ := json.Marshal(v)
		json.Unmarshal(b, &arr)
		if len(arr) != 2 {
			return "", nil, errors.New("create_time_between requires 2 values")
		}
		if tbl, col, ok := sch.FilterColumn("create_time_between"); ok {
			where = append(where, fmt.Sprintf("`%s`.%s BETWEEN ? AND ?", sch.TableName(tbl), escape(col)))
		}
		args = append(args, arr[0], arr[1])
	}
    var tv int
    if v, ok := req.Filters["type_eq"]; ok {
        switch t := v.(type) {
        case float64:
            tv = int(t)
        case int:
            tv = t
		case string:
			// simple digits parsing and label mapping
			_s := strings.TrimSpace(t)
			for i := 0; i < len(_s); i++ {
				c := _s[i]
				if c < '0' || c > '9' {
					continue
				}
				tv = tv*10 + int(c-'0')
			}
			if tv == 0 {
				if req.Datasource == "ymt" {
					if _s == "红包订单" {
						tv = 1
					}
					if _s == "直充卡密订单" {
						tv = 2
					}
					if _s == "立减金订单" {
						tv = 3
					}
				} else {
					if _s == "直充卡密" {
						tv = 1
					}
					if _s == "立减金" {
						tv = 2
					}
					if _s == "红包" {
						tv = 3
					}
				}
			}
        }
        if tv == 1 || tv == 2 || tv == 3 {
            if tbl, col, ok := sch.FilterColumn("type_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, tv)
        }
    }
	if v, ok := req.Filters["out_trade_no_eq"]; ok {
		s := toString(v)
		if s != "" {
			if tbl, col, ok := sch.FilterColumn("out_trade_no_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
			}
			args = append(args, s)
		}
	}
	if v, ok := req.Filters["account_eq"]; ok {
		s := toString(v)
		if s != "" {
			if tbl, col, ok := sch.FilterColumn("account_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
			}
			args = append(args, s)
		}
	}
	if v, ok := req.Filters["plan_id_eq"]; ok {
		s := toString(v)
		if s != "" && s != "0" {
			if tbl, col, ok := sch.FilterColumn("plan_id_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
			}
			args = append(args, s)
		}
	}
	if v, ok := req.Filters["key_batch_id_eq"]; ok {
		s := toString(v)
		if s != "" {
			if tbl, col, ok := sch.FilterColumn("key_batch_id_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
			}
			args = append(args, s)
		}
	}
	if v, ok := req.Filters["product_id_eq"]; ok {
		s := toString(v)
		if s != "" {
			if tbl, col, ok := sch.FilterColumn("product_id_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
			}
			args = append(args, s)
		}
	}
	if v, ok := req.Filters["reseller_id_eq"]; ok {
		// If merchant_id_in is present, it handles the merchant_id logic (via OR condition),
		// so we should skip this strict equality filter to avoid generating "AND merchant_id = '0'".
		if _, hasIn := req.Filters["merchant_id_in"]; !hasIn {
			s := toString(v)
			if s != "" {
				if tbl, col, ok := sch.FilterColumn("reseller_id_eq"); ok {
					where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
				}
				args = append(args, s)
			}
		}
	}
	if v, ok := req.Filters["code_batch_id_eq"]; ok {
		s := toString(v)
		if s != "" {
			if tbl, col, ok := sch.FilterColumn("code_batch_id_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
			}
			args = append(args, s)
		}
	}
	if v, ok := req.Filters["order_cash_cash_activity_id_eq"]; ok {
		s := toString(v)
		if s != "" {
			if tbl, col, ok := sch.FilterColumn("order_cash_cash_activity_id_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
			}
			args = append(args, s)
		}
	}
    if v, ok := req.Filters["order_voucher_channel_activity_id_eq"]; ok {
        // 易码通直充卡密订单不允许使用立减金批次号过滤
        if req.Datasource == "ymt" && tv == 2 {
            // skip
        } else {
            s := toString(v)
            if s != "" {
                if tbl, col, ok := sch.FilterColumn("order_voucher_channel_activity_id_eq"); ok {
                    where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
                }
                args = append(args, s)
            }
        }
    }
	if v, ok := req.Filters["voucher_batch_channel_activity_id_eq"]; ok {
		s := toString(v)
		if s != "" {
			if tbl, col, ok := sch.FilterColumn("voucher_batch_channel_activity_id_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
				args = append(args, s)
			}
		}
	}
	if v, ok := req.Filters["merchant_out_biz_no_eq"]; ok {
		s := toString(v)
		if s != "" {
			if tbl, col, ok := sch.FilterColumn("merchant_out_biz_no_eq"); ok {
				where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
			}
			args = append(args, s)
		}
	}
	// append necessary joins after collecting filter-driven needs
	joins := sch.BuildJoins(need, req.MainTable)
	for _, j := range joins {
		sb.WriteString(j)
	}
	if len(where) > 0 {
		sb.WriteString(" WHERE ")
		sb.WriteString(strings.Join(where, " AND "))
	}
	needDedupe := req.Datasource == "marketing" && req.MainTable == "order" && (need["order_voucher"] || need["voucher"] || need["voucher_batch"] || need["key_batch"] || need["code_batch"])
	if needDedupe {
		// Extract alias names in order
		aliases := make([]string, 0, len(cols))
		sources := make([]string, 0, len(cols))
		for _, c := range cols {
			pos := strings.LastIndex(c, " AS `")
			if pos < 0 {
				continue
			}
			alias := c[pos+5:]
			if len(alias) == 0 {
				continue
			}
			if alias[len(alias)-1] == '`' {
				alias = alias[:len(alias)-1]
			}
			aliases = append(aliases, alias)
			parts := strings.Split(alias, ".")
			src := ""
			if len(parts) >= 1 {
				src = parts[0]
			}
			sources = append(sources, src)
		}
		mt := sch.TableName(req.MainTable)
		pkCol, _ := sch.MapField(req.MainTable, "order_number")
		var out strings.Builder
		out.WriteString("SELECT ")
		for i := range aliases {
			if i > 0 {
				out.WriteString(",")
			}
			alias := aliases[i]
			src := sources[i]
			if src == "order" {
				out.WriteString("sub.`" + alias + "`")
			} else {
				out.WriteString("MIN(sub.`" + alias + "`) AS `" + alias + "`")
			}
		}
		out.WriteString(" FROM (")
		out.WriteString(sb.String())
		out.WriteString(") AS sub GROUP BY sub.`" + mt + "." + pkCol + "`")
		return out.String(), args, nil
	}
	return sb.String(), args, nil
}

func escape(s string) string {
	if s == "key" {
		return "`key`"
	}
	if s == "index" {
		return "`index`"
	}
	return s
}

func toString(v interface{}) string {
	switch t := v.(type) {
	case []byte:
		return string(t)
	case string:
		return t
	case int64:
		return strconv.FormatInt(t, 10)
	case int:
		return strconv.Itoa(t)
	case float64:
		return strconv.FormatFloat(t, 'f', -1, 64)
	case time.Time:
		return t.Format("2006-01-02 15:04:05")
	default:
		return ""
	}
}

// BuildCountSQL: minimal COUNT for filters-only joins, counting distinct main PK to avoid 1:N duplication
func BuildCountSQL(req BuildRequest, whitelist map[string]bool) (string, []interface{}, error) {
	if req.MainTable != "order" && req.MainTable != "order_info" {
		return "", nil, errors.New("unsupported main table")
	}
	sch := schema.Get(req.Datasource, req.MainTable)
	mt := sch.TableName(req.MainTable)
	pkCol, _ := sch.MapField(req.MainTable, "order_number")
	args := []interface{}{}
	where := []string{}
	need := map[string]bool{}
	// mark joins only needed by filters
	for k, _ := range req.Filters {
		if tbl, _, ok := sch.FilterColumn(k); ok {
			need[tbl] = true
		}
	}
	// Handle creator_in and merchant_id_in with OR logic if both exist
	var creatorArgs []interface{}
	hasCreator := false
	if v, ok := req.Filters["creator_in"]; ok {
		switch t := v.(type) {
		case []interface{}:
			creatorArgs = t
		case []int:
			for _, x := range t {
				creatorArgs = append(creatorArgs, x)
			}
		case []string:
			for _, x := range t {
				creatorArgs = append(creatorArgs, x)
			}
		}
		if len(creatorArgs) > 0 {
			hasCreator = true
		}
	}

	var merchantArgs []interface{}
	hasMerchant := false
	if v, ok := req.Filters["merchant_id_in"]; ok {
		switch t := v.(type) {
		case []interface{}:
			merchantArgs = t
		case []int:
			for _, x := range t {
				merchantArgs = append(merchantArgs, x)
			}
		case []string:
			for _, x := range t {
				merchantArgs = append(merchantArgs, x)
			}
		}
		if len(merchantArgs) > 0 {
			hasMerchant = true
		}
	}

	if hasCreator && hasMerchant {
		cTbl, cCol, cOk := sch.FilterColumn("creator_in")
		mTbl, mCol, mOk := sch.FilterColumn("merchant_id_in")
		if cOk && mOk {
			cPh := strings.Repeat("?,", len(creatorArgs))
			cPh = strings.TrimSuffix(cPh, ",")
			mPh := strings.Repeat("?,", len(merchantArgs))
			mPh = strings.TrimSuffix(mPh, ",")
			where = append(where, fmt.Sprintf("(`%s`.%s IN (%s) OR `%s`.%s IN (%s))",
				sch.TableName(cTbl), escape(cCol), cPh,
				sch.TableName(mTbl), escape(mCol), mPh))
			args = append(args, creatorArgs...)
			args = append(args, merchantArgs...)
		} else if cOk {
			ph := strings.Repeat("?,", len(creatorArgs))
			ph = strings.TrimSuffix(ph, ",")
			where = append(where, fmt.Sprintf("`%s`.%s IN (%s)", sch.TableName(cTbl), escape(cCol), ph))
			args = append(args, creatorArgs...)
		}
	} else if hasCreator {
		if tbl, col, ok := sch.FilterColumn("creator_in"); ok {
			ph := strings.Repeat("?,", len(creatorArgs))
			ph = strings.TrimSuffix(ph, ",")
			where = append(where, fmt.Sprintf("`%s`.%s IN (%s)", sch.TableName(tbl), escape(col), ph))
			args = append(args, creatorArgs...)
		}
	}

	// build WHERE from other filters
	for k, v := range req.Filters {
		if k == "creator_in" || k == "merchant_id_in" {
			continue
		}
		if k == "reseller_id_eq" {
			if _, has := req.Filters["merchant_id_in"]; has {
				continue
			}
		}
		if k == "plan_id_eq" && toString(v) == "0" {
			continue
		}
		if tbl, col, ok := sch.FilterColumn(k); ok {
			switch k {
			case "create_time_between":
				var arr []interface{}
				b, _ := json.Marshal(v)
				_ = json.Unmarshal(b, &arr)
				if len(arr) == 2 {
					where = append(where, fmt.Sprintf("`%s`.%s BETWEEN ? AND ?", sch.TableName(tbl), escape(col)))
					args = append(args, arr[0], arr[1])
				}
			default:
				s := toString(v)
				if s != "" {
					where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
					args = append(args, s)
				}
			}
		}
	}
	sb := strings.Builder{}
	sb.WriteString("SELECT COUNT(DISTINCT `" + mt + "`." + pkCol + ") FROM `" + mt + "`")
	for _, j := range sch.BuildJoins(need, req.MainTable) {
		sb.WriteString(j)
	}
	if len(where) > 0 {
		sb.WriteString(" WHERE ")
		sb.WriteString(strings.Join(where, " AND "))
	}
	return sb.String(), args, nil
}