diff --git a/flink-connector-jdbc/src/main/java/org/apache/flink/connector/jdbc/dialect/AbstractPostgresCompatibleDialect.java b/flink-connector-jdbc/src/main/java/org/apache/flink/connector/jdbc/dialect/AbstractPostgresCompatibleDialect.java
index 0ca425f30..b90b343df 100644
--- a/flink-connector-jdbc/src/main/java/org/apache/flink/connector/jdbc/dialect/AbstractPostgresCompatibleDialect.java
+++ b/flink-connector-jdbc/src/main/java/org/apache/flink/connector/jdbc/dialect/AbstractPostgresCompatibleDialect.java
@@ -50,12 +50,14 @@ public String getLimitClause(long limit) {
     @Override
     public Optional<String> getUpsertStatement(
             String tableName, String[] fieldNames, String[] uniqueKeyFields) {
+        Set<String> uniqueKeyFieldsSet = Arrays.stream(uniqueKeyFields).collect(Collectors.toSet());
         String uniqueColumns =
-                Arrays.stream(uniqueKeyFields)
+                uniqueKeyFieldsSet.stream()
                         .map(this::quoteIdentifier)
                         .collect(Collectors.joining(", "));
         String updateClause =
                 Arrays.stream(fieldNames)
+                        .filter(f -> !uniqueKeyFieldsSet.contains(f))
                         .map(f -> quoteIdentifier(f) + "=EXCLUDED." + quoteIdentifier(f))
                         .collect(Collectors.joining(", "));
         return Optional.of(