diff --git a/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt b/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
index ad0615f7cd..b6af32a32a 100644
--- a/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
+++ b/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
@@ -317,7 +317,7 @@ insertStatement =
   )
   break
   [
-    'ON DUPLICATE KEY UPDATE' 'SET' setClauses
+    'ON DUPLICATE KEY UPDATE' 'SET' setClauses [ 'WHERE' condition ]
   | 'ON DUPLICATE KEY IGNORE'
   | 'ON CONFLICT' ( 'ON CONSTRAINT' constraintName | '(' fieldNames ')' ) 'DO'
     (
diff --git a/jOOQ/src/main/java/org/jooq/impl/FieldMapForUpdate.java b/jOOQ/src/main/java/org/jooq/impl/FieldMapForUpdate.java
index e905a1fcad..36eef99e18 100644
--- a/jOOQ/src/main/java/org/jooq/impl/FieldMapForUpdate.java
+++ b/jOOQ/src/main/java/org/jooq/impl/FieldMapForUpdate.java
@@ -43,12 +43,15 @@ import static org.jooq.SQLDialect.POSTGRES;
 import static org.jooq.SQLDialect.SQLITE;
 // ...
 // ...
+import static org.jooq.impl.DSL.when;
 import static org.jooq.impl.Tools.flattenEntrySet;
+import static org.jooq.impl.Tools.DataKey.DATA_ON_DUPLICATE_KEY_WHERE;
 
 import java.util.EnumSet;
 import java.util.Map;
 
 import org.jooq.Clause;
+import org.jooq.Condition;
 import org.jooq.Context;
 import org.jooq.Field;
 import org.jooq.SQLDialect;
@@ -74,6 +77,7 @@ final class FieldMapForUpdate extends AbstractQueryPartMap<Field<?>, Field<?>> {
         this.assignmentClause = assignmentClause;
     }
 
+    @SuppressWarnings({ "unchecked", "rawtypes" })
     @Override
     public final void accept(Context<?> ctx) {
         if (size() > 0) {
@@ -98,9 +102,16 @@ final class FieldMapForUpdate extends AbstractQueryPartMap<Field<?>, Field<?>> {
                    .qualify(supportsQualify)
                    .visit(entry.getKey())
                    .qualify(restoreQualify)
-                   .sql(" = ")
-                   .visit(entry.getValue())
-                   .end(assignmentClause);
+                   .sql(" = ");
+
+                // [#8479] Emulate WHERE clause using CASE
+                Condition condition = (Condition) ctx.data(DATA_ON_DUPLICATE_KEY_WHERE);
+                if (condition != null)
+                    ctx.visit(when(condition, (Field) entry.getValue()).else_(entry.getKey()));
+                else
+                    ctx.visit(entry.getValue());
+
+                ctx.end(assignmentClause);
 
                 separator = ", ";
             }
diff --git a/jOOQ/src/main/java/org/jooq/impl/InsertQueryImpl.java b/jOOQ/src/main/java/org/jooq/impl/InsertQueryImpl.java
index 119ee44f68..4dfb8035b4 100644
--- a/jOOQ/src/main/java/org/jooq/impl/InsertQueryImpl.java
+++ b/jOOQ/src/main/java/org/jooq/impl/InsertQueryImpl.java
@@ -79,6 +79,7 @@ import static org.jooq.impl.Tools.fieldNameStrings;
 import static org.jooq.impl.Tools.fieldNames;
 import static org.jooq.impl.Tools.BooleanDataKey.DATA_CONSTRAINT_REFERENCE;
 import static org.jooq.impl.Tools.BooleanDataKey.DATA_INSERT_SELECT_WITHOUT_INSERT_COLUMN_LIST;
+import static org.jooq.impl.Tools.DataKey.DATA_ON_DUPLICATE_KEY_WHERE;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -305,9 +306,18 @@ final class InsertQueryImpl<R extends Record> extends AbstractStoreQuery<R> impl
                        .visit(K_ON_DUPLICATE_KEY_UPDATE)
                        .formatIndentStart()
                        .formatSeparator()
-                       .qualify(newQualify)
-                       .visit(updateMap)
-                       .qualify(oldQualify)
+                       .qualify(newQualify);
+
+                    // [#8479] Emulate WHERE clause using CASE
+                    if (condition.hasWhere())
+                        ctx.data(DATA_ON_DUPLICATE_KEY_WHERE, condition.getWhere());
+
+                    ctx.visit(updateMap);
+
+                    if (condition.hasWhere())
+                        ctx.data().remove(DATA_ON_DUPLICATE_KEY_WHERE);
+
+                    ctx.qualify(oldQualify)
                        .formatIndentEnd()
                        .end(INSERT_ON_DUPLICATE_KEY_UPDATE);
 
diff --git a/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java b/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
index 8cca34b587..26494752f9 100644
--- a/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
+++ b/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
@@ -1700,7 +1700,12 @@ final class ParserImpl implements Parser {
 
         if (parseKeywordIf(ctx, "ON")) {
             if (parseKeywordIf(ctx, "DUPLICATE KEY UPDATE SET")) {
-                returning = onDuplicate.onDuplicateKeyUpdate().set(parseSetClauseList(ctx));
+                InsertOnConflictWhereStep<?> where = onDuplicate.onDuplicateKeyUpdate().set(parseSetClauseList(ctx));
+
+                if (parseKeywordIf(ctx, "WHERE"))
+                    returning = where.where(parseCondition(ctx));
+                else
+                    returning = where;
             }
             else if (parseKeywordIf(ctx, "DUPLICATE KEY IGNORE")) {
                 returning = onDuplicate.onDuplicateKeyIgnore();
diff --git a/jOOQ/src/main/java/org/jooq/impl/Tools.java b/jOOQ/src/main/java/org/jooq/impl/Tools.java
index e2fef18f4c..6b57258653 100644
--- a/jOOQ/src/main/java/org/jooq/impl/Tools.java
+++ b/jOOQ/src/main/java/org/jooq/impl/Tools.java
@@ -549,7 +549,12 @@ final class Tools {
         /**
          * [#6583] The target table on which a DML operation operates on.
          */
-        DATA_DML_TARGET_TABLE
+        DATA_DML_TARGET_TABLE,
+
+        /**
+         * [#8479] There is a WHERE clause to be emulated for ON DUPLICATE KEY
+         */
+        DATA_ON_DUPLICATE_KEY_WHERE
     }
 
     /**