From 5d2658b519c82a35b40f032a2a850e6abc1ba47c Mon Sep 17 00:00:00 2001
From: Pace2Car <chenjiahao@apache.org>
Date: Thu, 12 Oct 2023 19:29:32 +0800
Subject: [PATCH] Add duplicate column check for add column to encrypt table

---
 .../token/generator/EncryptAlterTableTokenGenerator.java     | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/features/encrypt/core/src/main/java/org/apache/shardingsphere/encrypt/rewrite/token/generator/EncryptAlterTableTokenGenerator.java b/features/encrypt/core/src/main/java/org/apache/shardingsphere/encrypt/rewrite/token/generator/EncryptAlterTableTokenGenerator.java
index 6fa11e1e4ecc2..22312b69d9c9a 100644
--- a/features/encrypt/core/src/main/java/org/apache/shardingsphere/encrypt/rewrite/token/generator/EncryptAlterTableTokenGenerator.java
+++ b/features/encrypt/core/src/main/java/org/apache/shardingsphere/encrypt/rewrite/token/generator/EncryptAlterTableTokenGenerator.java
@@ -121,7 +121,10 @@ private Optional<SQLToken> getAddColumnPositionToken(final EncryptTable encryptT
         if (columnPositionSegment.isPresent()) {
             String columnName = columnPositionSegment.get().getColumnName().getIdentifier().getValue();
             if (encryptTable.isEncryptColumn(columnName)) {
-                return Optional.of(getPositionColumnToken(encryptTable.getEncryptColumn(columnName), segment.getColumnPosition().get()));
+                EncryptColumn encryptColumn = encryptTable.getEncryptColumn(columnName);
+                ShardingSpherePreconditions.checkState(encryptColumn.getName().equals(encryptColumn.getCipher().getName()),
+                        () -> new UnsupportedOperationException(String.format("Column %s is already exists", columnName)));
+                return Optional.of(getPositionColumnToken(encryptColumn, segment.getColumnPosition().get()));
             }
         }
         return Optional.empty();