m guide

yaooqinn · yaooqinn · commit d5c2a40b5bcb · 2019-11-22T14:17:50.000+08:00
diff --git a/docs/sql-migration-guide.md b/docs/sql-migration-guide.md
@@ -222,6 +222,8 @@ license: |
 
   - Since Spark 3.0, when casting interval values to string type, there is no "interval" prefix, e.g. `1 days 2 hours`. In Spark version 2.4 and earlier, the string contains the "interval" prefix like `interval 1 days 2 hours`.
 
+  - Since Spark 3.0, when casting string value to integral types, including tinyint, smallint, int and bigint type, the leading and trailing white spaces(<= ACSII 32) will be trimmed before convert to integral values, e.g. `cast(' 1 ' as int)` results `1`. In Spark version 2.4 and earlier, the result will be `null`.
+
 ## Upgrading from Spark SQL 2.4 to 2.4.1
 
   - The value of `spark.executor.heartbeatInterval`, when specified without units like "30" rather than "30s", was
