diff --git a/src/attributes/Attribute.mixins.ts b/src/attributes/Attribute.mixins.ts
index dd64e435..aebb3f40 100644
--- a/src/attributes/Attribute.mixins.ts
+++ b/src/attributes/Attribute.mixins.ts
@@ -1,4 +1,5 @@
 import AliasPredication from '../mixins/AliasPredication'
+import ConcatPredication from '../mixins/ConcatPredication'
 import Expressions from '../mixins/Expressions'
 import Math from '../mixins/Math'
 import OrderPredications from '../mixins/OrderPredications'
@@ -10,6 +11,7 @@ import Attribute from './Attribute'
 
 applyMixins(Attribute, [
   AliasPredication,
+  ConcatPredication,
   Expressions,
   Math,
   OrderPredications,
diff --git a/src/attributes/Attribute.ts b/src/attributes/Attribute.ts
index 07e3dfbd..1b01bc5f 100644
--- a/src/attributes/Attribute.ts
+++ b/src/attributes/Attribute.ts
@@ -1,6 +1,7 @@
 import type Relation from '../interfaces/Relation'
 
 import type AliasPredication from '../mixins/AliasPredication'
+import type ConcatPredication from '../mixins/ConcatPredication'
 import type Expressions from '../mixins/Expressions'
 import type Math from '../mixins/Math'
 import type OrderPredications from '../mixins/OrderPredications'
@@ -37,6 +38,7 @@ class Attribute {
 
 interface Attribute
   extends AliasPredication,
+    ConcatPredication,
     Expressions,
     Math,
     OrderPredications,
diff --git a/src/managers/SelectManager.ts b/src/managers/SelectManager.ts
index 73560b1d..597e6db7 100644
--- a/src/managers/SelectManager.ts
+++ b/src/managers/SelectManager.ts
@@ -195,7 +195,7 @@ class SelectManager extends TreeManager<SelectStatement> {
 
     if (typeof rel === 'string' || rel instanceof SQLLiteral) {
       rel = new SQLLiteral(rel)
-      if (rel.value.length <= 0) {
+      if (rel.length <= 0) {
         throw new EmptyJoinError()
       }
 
diff --git a/src/mixins/ConcatPredication.ts b/src/mixins/ConcatPredication.ts
new file mode 100644
index 00000000..3ca6a5fb
--- /dev/null
+++ b/src/mixins/ConcatPredication.ts
@@ -0,0 +1,7 @@
+import Concat from '../nodes/Concat'
+
+export default abstract class ConcatPredication {
+  concat(other: any): Concat {
+    return new Concat(this, other)
+  }
+}
diff --git a/src/mixins/Predications.ts b/src/mixins/Predications.ts
index f435d5af..8f65bb14 100644
--- a/src/mixins/Predications.ts
+++ b/src/mixins/Predications.ts
@@ -1,6 +1,5 @@
 import And from '../nodes/And'
 import Between from '../nodes/Between'
-import Concat from '../nodes/Concat'
 import DoesNotMatch from '../nodes/DoesNotMatch'
 import Equality from '../nodes/Equality'
 import GreaterThan from '../nodes/GreaterThan'
@@ -55,10 +54,6 @@ export default abstract class Predications {
     return others.map((v) => this.quotedNode(v))
   }
 
-  concat(other: any): Concat {
-    return new Concat(this, other)
-  }
-
   doesNotMatch(
     other: any,
     escape: any = null,
diff --git a/src/mixins/mod.ts b/src/mixins/mod.ts
index b7a12613..0e2cf9dd 100644
--- a/src/mixins/mod.ts
+++ b/src/mixins/mod.ts
@@ -1,4 +1,5 @@
 export { default as AliasPredication } from './AliasPredication'
+export { default as ConcatPredication } from './ConcatPredication'
 export { default as Expressions } from './Expressions'
 export { default as FactoryMethods } from './FactoryMethods'
 export { default as Math } from './Math'
diff --git a/src/nodes/Case.mixins.ts b/src/nodes/Case.mixins.ts
index 03f25837..495db4b1 100644
--- a/src/nodes/Case.mixins.ts
+++ b/src/nodes/Case.mixins.ts
@@ -1,10 +1,16 @@
 import AliasPredication from '../mixins/AliasPredication'
+import ConcatPredication from '../mixins/ConcatPredication'
 import OrderPredications from '../mixins/OrderPredications'
 import Predications from '../mixins/Predications'
 import applyMixins from '../mixins/applyMixins'
 
 import Case from './Case'
 
-applyMixins(Case, [AliasPredication, OrderPredications, Predications])
+applyMixins(Case, [
+  AliasPredication,
+  ConcatPredication,
+  OrderPredications,
+  Predications,
+])
 
 export default Case
diff --git a/src/nodes/Case.ts b/src/nodes/Case.ts
index 77d9e686..047beb20 100644
--- a/src/nodes/Case.ts
+++ b/src/nodes/Case.ts
@@ -4,6 +4,7 @@ import When from './When'
 import buildQuoted from './buildQuoted'
 
 import type AliasPredication from '../mixins/AliasPredication'
+import type ConcatPredication from '../mixins/ConcatPredication'
 import type OrderPredications from '../mixins/OrderPredications'
 import type Predications from '../mixins/Predications'
 
@@ -40,6 +41,10 @@ class Case extends Node {
   }
 }
 
-interface Case extends AliasPredication, OrderPredications, Predications {}
+interface Case
+  extends AliasPredication,
+    ConcatPredication,
+    OrderPredications,
+    Predications {}
 
 export default Case
diff --git a/src/nodes/Extract.mixins.ts b/src/nodes/Extract.mixins.ts
index 521b167a..de89993f 100644
--- a/src/nodes/Extract.mixins.ts
+++ b/src/nodes/Extract.mixins.ts
@@ -1,10 +1,16 @@
 import AliasPredication from '../mixins/AliasPredication'
+import ConcatPredication from '../mixins/ConcatPredication'
 import Predications from '../mixins/Predications'
 import WhenPredication from '../mixins/WhenPredication'
 import applyMixins from '../mixins/applyMixins'
 
 import Extract from './Extract'
 
-applyMixins(Extract, [AliasPredication, Predications, WhenPredication])
+applyMixins(Extract, [
+  AliasPredication,
+  ConcatPredication,
+  Predications,
+  WhenPredication,
+])
 
 export default Extract
diff --git a/src/nodes/Extract.ts b/src/nodes/Extract.ts
index 593190b1..155a30e7 100644
--- a/src/nodes/Extract.ts
+++ b/src/nodes/Extract.ts
@@ -1,6 +1,7 @@
 import Unary from './Unary'
 
 import type AliasPredication from '../mixins/AliasPredication'
+import type ConcatPredication from '../mixins/ConcatPredication'
 import type Predications from '../mixins/Predications'
 import type WhenPredication from '../mixins/WhenPredication'
 
@@ -14,6 +15,10 @@ class Extract extends Unary {
   }
 }
 
-interface Extract extends AliasPredication, Predications, WhenPredication {}
+interface Extract
+  extends AliasPredication,
+    ConcatPredication,
+    Predications,
+    WhenPredication {}
 
 export default Extract
diff --git a/src/nodes/Grouping.mixins.ts b/src/nodes/Grouping.mixins.ts
index e6e5b304..9b7ce8d2 100644
--- a/src/nodes/Grouping.mixins.ts
+++ b/src/nodes/Grouping.mixins.ts
@@ -1,9 +1,10 @@
+import ConcatPredication from '../mixins/ConcatPredication'
 import Predications from '../mixins/Predications'
 import WhenPredication from '../mixins/WhenPredication'
 import applyMixins from '../mixins/applyMixins'
 
 import Grouping from './Grouping'
 
-applyMixins(Grouping, [Predications, WhenPredication])
+applyMixins(Grouping, [ConcatPredication, Predications, WhenPredication])
 
 export default Grouping
diff --git a/src/nodes/Grouping.ts b/src/nodes/Grouping.ts
index ae64795e..cfbd3524 100644
--- a/src/nodes/Grouping.ts
+++ b/src/nodes/Grouping.ts
@@ -1,10 +1,11 @@
 import Unary from './Unary'
 
+import type ConcatPredication from '../mixins/ConcatPredication'
 import type Predications from '../mixins/Predications'
 import type WhenPredication from '../mixins/WhenPredication'
 
 class Grouping extends Unary {}
 
-interface Grouping extends Predications, WhenPredication {}
+interface Grouping extends ConcatPredication, Predications, WhenPredication {}
 
 export default Grouping
diff --git a/src/nodes/InfixOperation.mixins.ts b/src/nodes/InfixOperation.mixins.ts
index 08bffb37..f9ac83eb 100644
--- a/src/nodes/InfixOperation.mixins.ts
+++ b/src/nodes/InfixOperation.mixins.ts
@@ -1,4 +1,5 @@
 import AliasPredication from '../mixins/AliasPredication'
+import ConcatPredication from '../mixins/ConcatPredication'
 import Expressions from '../mixins/Expressions'
 import Math from '../mixins/Math'
 import OrderPredications from '../mixins/OrderPredications'
@@ -10,6 +11,7 @@ import InfixOperation from './InfixOperation'
 
 applyMixins(InfixOperation, [
   AliasPredication,
+  ConcatPredication,
   Expressions,
   Math,
   OrderPredications,
diff --git a/src/nodes/InfixOperation.ts b/src/nodes/InfixOperation.ts
index fbba3e2b..14eff551 100644
--- a/src/nodes/InfixOperation.ts
+++ b/src/nodes/InfixOperation.ts
@@ -1,6 +1,7 @@
 import Binary from './Binary'
 
 import type AliasPredication from '../mixins/AliasPredication'
+import type ConcatPredication from '../mixins/ConcatPredication'
 import type Expressions from '../mixins/Expressions'
 import type Math from '../mixins/Math'
 import type OrderPredications from '../mixins/OrderPredications'
@@ -19,6 +20,7 @@ class InfixOperation extends Binary {
 
 interface InfixOperation
   extends AliasPredication,
+    ConcatPredication,
     Expressions,
     Math,
     OrderPredications,
diff --git a/src/nodes/SQLFunction.mixins.ts b/src/nodes/SQLFunction.mixins.ts
index d45e141c..3d7f570c 100644
--- a/src/nodes/SQLFunction.mixins.ts
+++ b/src/nodes/SQLFunction.mixins.ts
@@ -1,3 +1,4 @@
+import ConcatPredication from '../mixins/ConcatPredication'
 import OrderPredications from '../mixins/OrderPredications'
 import Predications from '../mixins/Predications'
 import WhenPredication from '../mixins/WhenPredication'
@@ -7,6 +8,7 @@ import applyMixins from '../mixins/applyMixins'
 import SQLFunction from './SQLFunction'
 
 applyMixins(SQLFunction, [
+  ConcatPredication,
   OrderPredications,
   Predications,
   WhenPredication,
diff --git a/src/nodes/SQLFunction.ts b/src/nodes/SQLFunction.ts
index b411dbb3..a04fae36 100644
--- a/src/nodes/SQLFunction.ts
+++ b/src/nodes/SQLFunction.ts
@@ -1,6 +1,7 @@
 import Node from './Node'
 import SQLLiteral from './SQLLiteral'
 
+import type ConcatPredication from '../mixins/ConcatPredication'
 import type OrderPredications from '../mixins/OrderPredications'
 import type Predications from '../mixins/Predications'
 import type WhenPredication from '../mixins/WhenPredication'
@@ -31,7 +32,8 @@ class SQLFunction extends Node {
 }
 
 interface SQLFunction
-  extends OrderPredications,
+  extends ConcatPredication,
+    OrderPredications,
     Predications,
     WhenPredication,
     WindowPredication {}
diff --git a/src/nodes/SQLLiteral.ts b/src/nodes/SQLLiteral.ts
index eb90dcac..20a7b52b 100644
--- a/src/nodes/SQLLiteral.ts
+++ b/src/nodes/SQLLiteral.ts
@@ -4,21 +4,7 @@ import type OrderPredications from '../mixins/OrderPredications'
 import type Predications from '../mixins/Predications'
 import type WhenPredication from '../mixins/WhenPredication'
 
-class SQLLiteral {
-  public value: string
-
-  constructor(value: string | SQLLiteral) {
-    if (value instanceof SQLLiteral) {
-      this.value = value.value
-    } else {
-      this.value = value
-    }
-  }
-
-  toString(): string {
-    return this.value
-  }
-}
+class SQLLiteral extends String {}
 
 interface SQLLiteral
   extends AliasPredication,
diff --git a/src/nodes/UnaryOperation.mixins.ts b/src/nodes/UnaryOperation.mixins.ts
index 31d06fcf..582b28c5 100644
--- a/src/nodes/UnaryOperation.mixins.ts
+++ b/src/nodes/UnaryOperation.mixins.ts
@@ -1,4 +1,5 @@
 import AliasPredication from '../mixins/AliasPredication'
+import ConcatPredication from '../mixins/ConcatPredication'
 import Expressions from '../mixins/Expressions'
 import Math from '../mixins/Math'
 import OrderPredications from '../mixins/OrderPredications'
@@ -10,6 +11,7 @@ import UnaryOperation from './UnaryOperation'
 
 applyMixins(UnaryOperation, [
   AliasPredication,
+  ConcatPredication,
   Expressions,
   Math,
   OrderPredications,
diff --git a/src/nodes/UnaryOperation.ts b/src/nodes/UnaryOperation.ts
index 5d7ed31e..eb9cd5a4 100644
--- a/src/nodes/UnaryOperation.ts
+++ b/src/nodes/UnaryOperation.ts
@@ -3,6 +3,7 @@ import Unary from './Unary'
 import type Attribute from '../attributes/Attribute'
 
 import type AliasPredication from '../mixins/AliasPredication'
+import type ConcatPredication from '../mixins/ConcatPredication'
 import type Expressions from '../mixins/Expressions'
 import type Math from '../mixins/Math'
 import type OrderPredications from '../mixins/OrderPredications'
@@ -21,6 +22,7 @@ class UnaryOperation extends Unary {
 
 interface UnaryOperation
   extends AliasPredication,
+    ConcatPredication,
     Expressions,
     Math,
     OrderPredications,