@@ -28,7 +28,7 @@ public class WithItem<K extends ParenthesedStatement> implements Serializable {
     private Alias alias;
     private List<SelectItem<?>> withItemList;
     private boolean recursive = false;
-
+    private boolean usingNot = false;
     private boolean materialized = false;
 
     public WithItem(K statement, Alias alias) {
@@ -90,6 +90,24 @@ public void setMaterialized(boolean materialized) {
         this.materialized = materialized;
     }
 
+    public K getStatement() {
+        return statement;
+    }
+
+    public WithItem<K> setStatement(K statement) {
+        this.statement = statement;
+        return this;
+    }
+
+    public boolean isUsingNot() {
+        return usingNot;
+    }
+
+    public WithItem<K> setUsingNot(boolean usingNot) {
+        this.usingNot = usingNot;
+        return this;
+    }
+
     /**
      * The {@link SelectItem}s in this WITH (for example the A,B,C in "WITH mywith (A,B,C) AS ...")
      *
@@ -119,7 +137,11 @@ public String toString() {
             builder.append(")");
         }
         builder.append(" AS ");
-        builder.append(materialized ? "MATERIALIZED " : "");
+        if (materialized) {
+            builder.append(usingNot
+                    ? "NOT MATERIALIZED "
+                    : "MATERIALIZED ");
+        }
         builder.append(statement);
         return builder.toString();
     }
@@ -144,6 +166,13 @@ public WithItem<?> withRecursive(boolean recursive, boolean materialized) {
         return this;
     }
 
+    public WithItem<?> withRecursive(boolean recursive, boolean usingNot, boolean materialized) {
+        this.setRecursive(recursive);
+        this.setUsingNot(usingNot);
+        this.setMaterialized(materialized);
+        return this;
+    }
+
     public WithItem<?> addWithItemList(SelectItem<?>... withItemList) {
         List<SelectItem<?>> collection =
                 Optional.ofNullable(getWithItemList()).orElseGet(ArrayList::new);
 
@@ -718,7 +718,9 @@ public <S> StringBuilder visit(WithItem<?> withItem, S context) {
         }
         builder.append(" AS ");
         if (withItem.isMaterialized()) {
-            builder.append("MATERIALIZED ");
+            builder.append(withItem.isUsingNot()
+                    ? "NOT MATERIALIZED "
+                    : "MATERIALIZED ");
         }
         StatementDeParser statementDeParser =
                 new StatementDeParser((ExpressionDeParser) expressionVisitor, this, builder);
 
@@ -3348,6 +3348,7 @@ WithItem<?> WithItem() #WithItem:
 {
     boolean recursive = false;
     boolean materialized = false;
+    boolean usingNot = false;
     String name;
     List<SelectItem<?>> selectItems = null;
     ParenthesedStatement statement;
@@ -3357,7 +3358,7 @@ WithItem<?> WithItem() #WithItem:
      name=RelObjectName()
      [ "(" selectItems=SelectItemsList() ")" ]
      <K_AS>
-     [ LOOKAHEAD(2) <K_MATERIALIZED>  { materialized = true; } ]
+     [ LOOKAHEAD(2) [ <K_NOT> { usingNot = true; } ] <K_MATERIALIZED>  { materialized = true; } ]
      (
          LOOKAHEAD(2) statement = ParenthesedSelect()
          |
@@ -3370,7 +3371,7 @@ WithItem<?> WithItem() #WithItem:
      {
         WithItem<?> withItem = new WithItem(statement, new Alias(name, false));
         return withItem
-            .withRecursive(recursive, materialized)
+            .withRecursive(recursive, usingNot, materialized)
             .withWithItemList(selectItems);
      }
 }
 
@@ -0,0 +1,20 @@
+package net.sf.jsqlparser.statement.select;
+
+import net.sf.jsqlparser.JSQLParserException;
+import net.sf.jsqlparser.test.TestUtils;
+import org.junit.jupiter.api.Test;
+
+class WithItemTest {
+
+    @Test
+    void testNotMaterializedIssue2251() throws JSQLParserException {
+        String sqlStr = "WITH devices AS NOT MATERIALIZED (\n"
+                + "  SELECT\n"
+                + "    d.uuid AS device_uuid\n"
+                + "  FROM active_devices d\n"
+                + ")\n"
+                + "SELECT 1;";
+        TestUtils.assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+    }
+
+}
Original file line number	Diff line number	Diff line change
`@@ -718,7 +718,9 @@ public <S> StringBuilder visit(WithItem<?> withItem, S context) {`
`718`	`718`	`}`
`719`	`719`	`builder.append(" AS ");`
`720`	`720`	`if (withItem.isMaterialized()) {`
`721`		`- builder.append("MATERIALIZED ");`
	`721`	`+ builder.append(withItem.isUsingNot()`
	`722`	`+ ? "NOT MATERIALIZED "`
	`723`	`+ : "MATERIALIZED ");`
`722`	`724`	`}`
`723`	`725`	`StatementDeParser statementDeParser =`
`724`	`726`	`new StatementDeParser((ExpressionDeParser) expressionVisitor, this, builder);`
Original file line number	Diff line number	Diff line change
`@@ -3348,6 +3348,7 @@ WithItem<?> WithItem() #WithItem:`
`3348`	`3348`	`{`
`3349`	`3349`	`boolean recursive = false;`
`3350`	`3350`	`boolean materialized = false;`
	`3351`	`+ boolean usingNot = false;`
`3351`	`3352`	`String name;`
`3352`	`3353`	`List<SelectItem<?>> selectItems = null;`
`3353`	`3354`	`ParenthesedStatement statement;`
`@@ -3357,7 +3358,7 @@ WithItem<?> WithItem() #WithItem:`
`3357`	`3358`	`name=RelObjectName()`
`3358`	`3359`	`[ "(" selectItems=SelectItemsList() ")" ]`
`3359`	`3360`	`<K_AS>`
`3360`		`- [ LOOKAHEAD(2) <K_MATERIALIZED> { materialized = true; } ]`
	`3361`	`+ [ LOOKAHEAD(2) [ <K_NOT> { usingNot = true; } ] <K_MATERIALIZED> { materialized = true; } ]`
`3361`	`3362`	`(`
`3362`	`3363`	`LOOKAHEAD(2) statement = ParenthesedSelect()`
`3363`	`3364`	`\|`
`@@ -3370,7 +3371,7 @@ WithItem<?> WithItem() #WithItem:`
`3370`	`3371`	`{`
`3371`	`3372`	`WithItem<?> withItem = new WithItem(statement, new Alias(name, false));`
`3372`	`3373`	`return withItem`
`3373`		`- .withRecursive(recursive, materialized)`
	`3374`	`+ .withRecursive(recursive, usingNot, materialized)`
`3374`	`3375`	`.withWithItemList(selectItems);`
`3375`	`3376`	`}`
`3376`	`3377`	`}`