Avoid selection of duplicate columns

Author: IAM20

spring-data-jdbc-plus-sql/src/main/java/com/navercorp/spring/data/jdbc/plus/sql/convert/SqlGenerator.java

@@ -612,7 +612,7 @@ private SelectBuilder.SelectWhere selectBuilder(Collection<SqlIdentifier> keyCol
 
 		Table table = getTable();
 
-		List<Expression> columnExpressions = new ArrayList<>();
+		Set<Expression> columnExpressions = new LinkedHashSet<>();
 
 		List<Join> joinTables = new ArrayList<>();
 		for (PersistentPropertyPath<RelationalPersistentProperty> path : mappingContext