sunxiaoguang commented on code in PR #49453:
URL: https://github.com/apache/spark/pull/49453#discussion_r1971726586


##########
connector/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/v2/MySQLIntegrationSuite.scala:
##########
@@ -241,6 +241,84 @@ class MySQLIntegrationSuite extends 
DockerJDBCIntegrationV2Suite with V2JDBCTest
     assert(rows10(0).getString(0) === "amy")
     assert(rows10(1).getString(0) === "alex")
   }
+
+  // MySQL Connector/J uses collation 'utf8mb4_0900_ai_ci' as collation for 
connection.
+  // The MySQL server 9.1.0 uses collation 'utf8mb4_0900_ai_ci' for database 
by default.
+  // This method uses string colume directly as the result of cast has the 
same collation.
+  def testCastStringTarget(stringLiteral: String, stringCol: String): String = 
stringCol
+
+  test("SPARK-50793: MySQL JDBC Connector failed to cast some types") {
+    val tableName = catalogName + ".test_cast_function"
+    withTable(tableName) {
+      val stringValue = "0"
+      val stringLiteral = "'0'"
+      val stringCol = "string_col"
+      val longValue = 0L
+      val longCol = "long_col"
+      val binaryValue = Array[Byte](0x30)
+      val binaryLiteral = "x'30'"
+      val binaryCol = "binary_col"
+      val doubleValue = 0.0
+      val doubleLiteral = "0.0"
+      val doubleCol = "double_col"
+      // CREATE table to use types defined in Spark SQL
+      sql(
+        s"CREATE TABLE $tableName ($stringCol STRING, $longCol LONG, " +
+          s"$binaryCol BINARY, $doubleCol DOUBLE)")
+      sql(
+        s"INSERT INTO $tableName VALUES($stringLiteral, $longValue, 
$binaryLiteral, $doubleValue)")
+
+      def testCast(
+          castType: String,
+          sourceCol: String,
+          targetCol: String,
+          targetDataType: DataType,
+          targetValue: Any): Unit = {
+        val sql = s"SELECT CAST($sourceCol AS $castType) AS target " +
+          s"FROM $tableName WHERE CAST($sourceCol AS $castType) = $targetCol"
+        val df = spark.sql(sql)

Review Comment:
   Supporting collation to JDBC connectors sounds like a large piece of work. 
We need to support it on all the  connectors right?
   
   How about we come up with acceptable test cases for this PR and try to work 
on real collation support in connectors as a separate piece of work.  For 
example, let's say we just do not verify if cast works with both columns and 
literals. Or use the approach we are taking right now, which fix the 
collation_connection incompatibility issue between MariaDB Connector/J and 
MySQL Server. 



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org

Reply via email to