Merge pull request #6924 from dataease/pr@dev-v2@fix_null_value_linkage

fix: 空值联动异常

core/core-backend/src/main/java/io/dataease/engine/utils/SQLUtils.java

@@ -1,11 +1,13 @@
 package io.dataease.engine.utils;
 
+import java.util.Optional;
+
 /**
  * @Author Junjun
  */
 public class SQLUtils {
     public static String transKeyword(String value) {
-        return value.replaceAll("'", "\\\\'");
+        return Optional.ofNullable(value).orElse("").replaceAll("'", "\\\\'");
     }
 
     public static String buildOriginPreviewSql(String sql, int limit, int offset) {