diff --git a/builder_x.go b/builder_x.go
index 0ec4eac..c09a7fd 100644
--- a/builder_x.go
+++ b/builder_x.go
@@ -79,6 +79,9 @@ func (x *BuilderX) ResultKeys(resultKeys ...string) *BuilderX {
 }
 
 func (x *BuilderX) Source(po Po) *BuilderX {
+	if len(x.sxs) == 0 {
+		x.sxs = append(x.sxs, new(SourceX))
+	}
 	x.sxs[0].po = po
 	return x
 }
@@ -117,28 +120,41 @@ func (x *BuilderX) Agg(fn string, vs ...interface{}) *BuilderX {
 	return x
 }
 
-func (builder *BuilderX) Build() *Built {
-	if builder == nil {
+func (x *BuilderX) Build() *Built {
+	if x == nil {
 		panic("sqlxb.Builder is nil")
 	}
-	builder.optimizeSourceBuilder()
+	x.optimizeSourceBuilder()
 	built := Built{
-		ResultKeys:  builder.resultKeys,
-		ConditionX:  builder.bbs,
-		Sorts:       builder.sorts,
-		Aggs:        builder.aggs,
-		Havings:     builder.havings,
-		GroupBys:    builder.groupBys,
-		OrSourceSql: builder.orSourceSql,
-		Sbs:         builder.sxs,
-		Svs:         builder.svs,
-
-		Po: builder.po,
+		ResultKeys:  x.resultKeys,
+		ConditionX:  x.bbs,
+		Sorts:       x.sorts,
+		Aggs:        x.aggs,
+		Havings:     x.havings,
+		GroupBys:    x.groupBys,
+		OrSourceSql: x.orSourceSql,
+		Sbs:         x.sxs,
+		Svs:         x.svs,
+
+		Po: x.po,
 	}
 
-	if builder.pageBuilder != nil {
-		built.PageCondition = &builder.pageBuilder.condition
+	if x.pageBuilder != nil {
+		built.PageCondition = &x.pageBuilder.condition
 	}
 
 	return &built
 }
+
+func (x *BuilderX) Sub(s string, sub func(sub *BuilderX)) *BuilderX {
+
+	b := new(BuilderX)
+	sub(b)
+	bb := Bb{
+		op:    SUB,
+		key:   s,
+		value: b,
+	}
+	x.bbs = append(x.bbs, bb)
+	return x
+}
diff --git a/oper.go b/oper.go
index 865599f..824d9ec 100644
--- a/oper.go
+++ b/oper.go
@@ -7,7 +7,7 @@
 // (the "License"); you may not use this file except in compliance with
 // the License.  You may obtain a copy of the License at
 //
-//     http://www.apache.org/licenses/LICENSE-2.0
+//	http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ -19,6 +19,7 @@ package sqlxb
 const (
 	X        = ""
 	AGG      = ""
+	SUB      = "SUB"
 	AND      = "AND"
 	OR       = "OR"
 	AND_SUB  = AND
diff --git a/source_builder_optimization.go b/source_builder_optimization.go
index eba84ea..5f96576 100644
--- a/source_builder_optimization.go
+++ b/source_builder_optimization.go
@@ -20,20 +20,20 @@ import (
 	"strings"
 )
 
-func (builder *BuilderX) WithoutOptimization() *BuilderX {
-	builder.isWithoutOptimization = true
-	return builder
+func (x *BuilderX) WithoutOptimization() *BuilderX {
+	x.isWithoutOptimization = true
+	return x
 }
 
-func (builder *BuilderX) optimizeSourceBuilder() {
-	if builder.isWithoutOptimization {
+func (x *BuilderX) optimizeSourceBuilder() {
+	if x.isWithoutOptimization {
 		return
 	}
-	if len(builder.resultKeys) == 0 || len(builder.sxs) < 2 {
+	if len(x.resultKeys) == 0 || len(x.sxs) < 2 {
 		return
 	}
 
-	builder.removeSourceBuilder(builder.sxs, func(useds *[]*SourceX, ele *SourceX, i int) bool {
+	x.removeSourceBuilder(x.sxs, func(useds *[]*SourceX, ele *SourceX, i int) bool {
 
 		if ele.sub != nil && (ele.join != nil && !strings.Contains(ele.join.join, "LEFT")) {
 			return false
@@ -44,7 +44,7 @@ func (builder *BuilderX) optimizeSourceBuilder() {
 				return false
 			}
 		}
-		for _, v := range *builder.conds() {
+		for _, v := range *x.conds() {
 			if ele.po != nil && strings.Contains(v, ele.po.TableName()+".") { //has return or condition
 				return false
 			}
@@ -54,8 +54,8 @@ func (builder *BuilderX) optimizeSourceBuilder() {
 		}
 
 		//target
-		for j := len(builder.sxs) - 1; j > i; j-- {
-			var sb = builder.sxs[j]
+		for j := len(x.sxs) - 1; j > i; j-- {
+			var sb = x.sxs[j]
 
 			if sb.join != nil && sb.join.on != nil && sb.join.on.bbs != nil {
 				for _, bb := range sb.join.on.bbs {
@@ -74,13 +74,13 @@ func (builder *BuilderX) optimizeSourceBuilder() {
 	})
 }
 
-func (builder *BuilderX) conds() *[]string {
+func (x *BuilderX) conds() *[]string {
 	condArr := []string{}
-	for _, v := range builder.resultKeys {
+	for _, v := range x.resultKeys {
 		condArr = append(condArr, v)
 	}
 
-	bbps := builder.CondBuilder.bbs
+	bbps := x.CondBuilder.bbs
 
 	if bbps != nil {
 		for _, v := range bbps {
@@ -88,8 +88,8 @@ func (builder *BuilderX) conds() *[]string {
 		}
 	}
 
-	if len(builder.sxs) > 0 {
-		for _, sb := range builder.sxs {
+	if len(x.sxs) > 0 {
+		for _, sb := range x.sxs {
 			if sb.join != nil && sb.join.on != nil && sb.join.on.bbs != nil {
 				for i, bb := range sb.join.on.bbs {
 					if i > 0 {
@@ -102,7 +102,7 @@ func (builder *BuilderX) conds() *[]string {
 	return &condArr
 }
 
-func (builder *BuilderX) removeSourceBuilder(sbs []*SourceX, canRemove canRemove) {
+func (x *BuilderX) removeSourceBuilder(sbs []*SourceX, canRemove canRemove) {
 	useds := []*SourceX{}
 	j := 0
 	leng := len(sbs)
@@ -119,10 +119,10 @@ func (builder *BuilderX) removeSourceBuilder(sbs []*SourceX, canRemove canRemove
 	j = 0
 	if length < leng {
 		for i := length - 1; i > -1; i-- { //reverse
-			(builder.sxs)[j] = useds[i]
+			(x.sxs)[j] = useds[i]
 			j++
 		}
-		builder.sxs = (builder.sxs)[:j]
+		x.sxs = (x.sxs)[:j]
 	}
 }
 
diff --git a/to_result_key.go b/to_result_key.go
index 709c5cf..53ea378 100644
--- a/to_result_key.go
+++ b/to_result_key.go
@@ -7,7 +7,7 @@
 // (the "License"); you may not use this file except in compliance with
 // the License.  You may obtain a copy of the License at
 //
-//     http://www.apache.org/licenses/LICENSE-2.0
+//	http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ -57,7 +57,7 @@ func buildResultKey(key string, km map[string]string) string {
 	return key
 }
 
-func (built *Built) toResultKeyScript(bp *strings.Builder, km map[string]string) {
+func (built *Built) toResultKeySql(bp *strings.Builder, km map[string]string) {
 	bp.WriteString(SELECT)
 	if built.ResultKeys == nil {
 		bp.WriteString(STAR)
@@ -80,7 +80,7 @@ func (built *Built) toResultKeyScript(bp *strings.Builder, km map[string]string)
 	}
 }
 
-func (built *Built) toResultKeyScriptOfCount(bpCount *strings.Builder) {
+func (built *Built) toResultKeySqlOfCount(bpCount *strings.Builder) {
 	if built.ResultKeys != nil && len(built.ResultKeys) > 0 {
 		bpCount.WriteString(COUNT_KEY_SCRIPT_LEFT)
 		bpCount.WriteString(built.ResultKeys[0])
diff --git a/to_source_script_by_builder.go b/to_source_sql_by_builder.go
similarity index 89%
rename from to_source_script_by_builder.go
rename to to_source_sql_by_builder.go
index d9a7f43..bcbf9f2 100644
--- a/to_source_script_by_builder.go
+++ b/to_source_sql_by_builder.go
@@ -21,7 +21,7 @@ import (
 	"strings"
 )
 
-func (built *Built) toSourceScriptBySql(bp *strings.Builder) bool {
+func (built *Built) toSourceSqlBySql(bp *strings.Builder) bool {
 	if (len(built.Sbs) == 1) && (built.OrSourceSql != "") {
 		var sql = strings.Trim(built.OrSourceSql, SPACE)
 		if strings.HasPrefix(sql, "FROM") {
@@ -33,7 +33,7 @@ func (built *Built) toSourceScriptBySql(bp *strings.Builder) bool {
 	return false
 }
 
-func (built *Built) toSourceScriptByBuilder(vs *[]interface{}, sb *SourceX, bp *strings.Builder) {
+func (built *Built) toSourceSqlByBuilder(vs *[]interface{}, sb *SourceX, bp *strings.Builder) {
 	if sb.join != nil { //JOIN
 		bp.WriteString(SPACE)
 		bp.WriteString(sb.join.join)
@@ -62,7 +62,7 @@ func (built *Built) toSourceScriptByBuilder(vs *[]interface{}, sb *SourceX, bp *
 			bp.WriteString(sb.s)
 		} else {
 			bp.WriteString(ON_SCRIPT)
-			built.toConditionScript(sb.join.on.bbs, bp, vs, nil)
+			built.toConditionSql(sb.join.on.bbs, bp, vs, nil)
 		}
 	}
 }
diff --git a/to_sql.go b/to_sql.go
index f62ede3..4047d12 100644
--- a/to_sql.go
+++ b/to_sql.go
@@ -39,27 +39,27 @@ type Built struct {
 	Po Po
 }
 
-func (built *Built) toSourceScriptOfCount(bpCount *strings.Builder) {
-	built.toSourceScript(nil, bpCount)
+func (built *Built) toSourceSqlOfCount(bpCount *strings.Builder) {
+	built.toSourceSql(nil, bpCount)
 }
 
-func (built *Built) toConditionScriptOfCount(bbs []Bb, bpCount *strings.Builder) {
-	built.toConditionScript(bbs, bpCount, nil, nil)
+func (built *Built) toConditionSqlOfCount(bbs []Bb, bpCount *strings.Builder) {
+	built.toConditionSql(bbs, bpCount, nil, nil)
 }
 
 func (built *Built) toGroupBySqlOfCount(bpCount *strings.Builder) {
 	built.toGroupBySql(bpCount)
 }
 
-func (built *Built) toSourceScript(vs *[]interface{}, bp *strings.Builder) {
+func (built *Built) toSourceSql(vs *[]interface{}, bp *strings.Builder) {
 	if built.Po == nil {
 
-		if built.toSourceScriptBySql(bp) {
+		if built.toSourceSqlBySql(bp) {
 			return
 		}
 
 		for _, sb := range built.Sbs {
-			built.toSourceScriptByBuilder(vs, sb, bp)
+			built.toSourceSqlByBuilder(vs, sb, bp)
 		}
 	} else {
 		bp.WriteString(built.Po.TableName())
@@ -101,8 +101,23 @@ func (built *Built) toBb(bb Bb, bp *strings.Builder, vs *[]interface{}) {
 			return
 		}
 		bp.WriteString(BEGIN_SUB)
-		built.toConditionScript(bb.subs, bp, vs, nil)
+		built.toConditionSql(bb.subs, bp, vs, nil)
 		bp.WriteString(END_SUB)
+	case SUB:
+		var bx = *bb.value.(*BuilderX)
+		ss, _ := bx.Build().sqlData(vs, nil)
+		ss = BEGIN_SUB + ss + END_SUB
+		if bb.key != "" {
+			if strings.Contains(bb.key, PLACE_HOLDER) {
+				bp.WriteString(strings.ReplaceAll(bb.key, PLACE_HOLDER, ss))
+			} else {
+				bp.WriteString(bb.key)
+				bp.WriteString(SPACE)
+				bp.WriteString(ss)
+			}
+		} else {
+			bp.WriteString(ss)
+		}
 	default:
 		bp.WriteString(bb.key)
 		bp.WriteString(SPACE)
@@ -114,7 +129,7 @@ func (built *Built) toBb(bb Bb, bp *strings.Builder, vs *[]interface{}) {
 	}
 }
 
-func (built *Built) toConditionScript(bbs []Bb, bp *strings.Builder, vs *[]interface{}, filterLast func() *Bb) {
+func (built *Built) toConditionSql(bbs []Bb, bp *strings.Builder, vs *[]interface{}, filterLast func() *Bb) {
 
 	length := len(bbs)
 
@@ -179,7 +194,7 @@ func (built *Built) toHavingSql(vs *[]interface{}, bp *strings.Builder) {
 		return
 	}
 	bp.WriteString(HAVING)
-	built.toConditionScript(built.Havings, bp, vs, nil)
+	built.toConditionSql(built.Havings, bp, vs, nil)
 }
 
 func (built *Built) toHavingSqlOfCount(bp *strings.Builder) {
@@ -241,7 +256,7 @@ func (built *Built) countBuilder() *strings.Builder {
 func (built *Built) SqlOfCondition() ([]interface{}, string) {
 	vs := []interface{}{}
 	sb := strings.Builder{}
-	built.toConditionScript(built.ConditionX, &sb, &vs, built.filterLast)
+	built.toConditionSql(built.ConditionX, &sb, &vs, built.filterLast)
 	conditionSql := sb.String()
 	return vs, conditionSql
 }
@@ -284,11 +299,11 @@ func (built *Built) Sql() ([]interface{}, string, string, map[string]string) {
 
 func (built *Built) sqlData(vs *[]interface{}, km map[string]string) (string, map[string]string) {
 	sb := strings.Builder{}
-	built.toResultKeyScript(&sb, km)
+	built.toResultKeySql(&sb, km)
 	built.sqlFrom(&sb)
-	built.toSourceScript(vs, &sb)
+	built.toSourceSql(vs, &sb)
 	built.sqlWhere(&sb)
-	built.toConditionScript(built.ConditionX, &sb, vs, built.filterLast)
+	built.toConditionSql(built.ConditionX, &sb, vs, built.filterLast)
 	built.toAggSql(vs, &sb)
 	built.toGroupBySql(&sb)
 	built.toHavingSql(vs, &sb)
@@ -303,11 +318,11 @@ func (built *Built) sqlCount() string {
 	if sbCount == nil {
 		return ""
 	}
-	built.toResultKeyScriptOfCount(sbCount)
+	built.toResultKeySqlOfCount(sbCount)
 	built.countSqlFrom(sbCount)
-	built.toSourceScriptOfCount(sbCount)
+	built.toSourceSqlOfCount(sbCount)
 	built.countSqlWhere(sbCount)
-	built.toConditionScriptOfCount(built.ConditionX, sbCount)
+	built.toConditionSqlOfCount(built.ConditionX, sbCount)
 	built.toAggSqlOfCount(sbCount)
 	built.toGroupBySqlOfCount(sbCount)
 	built.toHavingSqlOfCount(sbCount)