DBZ-6554 Added method to override alter statement field delimiter, setting it to comma for MySQL dialect

debezium-connector-jdbc/src/main/java/io/debezium/connector/jdbc/dialect/DatabaseDialect.java

@@ -96,6 +96,15 @@ public interface DatabaseDialect {
      */
     String getAlterTableStatement(TableDescriptor table, SinkRecordDescriptor record, Set<String> missingFields);
 
+    /**
+     * Gets the field delimeter used when contructing {@code ALTER TABLE} statements.
+     *
+     * @return the field delimeter for alter table SQL statement
+     */
+    default String getAlterTableStatementFieldDelimiter() {
+        return " ";
+    }
+
     /**
      * Construct a {@code INSERT INTO} statement specific for this dialect.
      *

debezium-connector-jdbc/src/main/java/io/debezium/connector/jdbc/dialect/GeneralDatabaseDialect.java

@@ -292,7 +292,7 @@ public String getAlterTableStatement(TableDescriptor table, SinkRecordDescriptor
         builder.append("ALTER TABLE ");
         builder.append(getQualifiedTableName(table.getId()));
         builder.append(" ");
-        builder.appendList(" ", missingFields, (name) -> {
+        builder.appendList(getAlterTableStatementFieldDelimiter(), missingFields, (name) -> {
             final FieldDescriptor field = record.getFields().get(name);
             final StringBuilder addColumnSpec = new StringBuilder();
             addColumnSpec.append("ADD ");

debezium-connector-jdbc/src/main/java/io/debezium/connector/jdbc/dialect/mysql/MySqlDatabaseDialect.java

@@ -111,6 +111,11 @@ protected void registerTypes() {
         registerType(MapToJsonType.INSTANCE);
     }
 
+    @Override
+    public String getAlterTableStatementFieldDelimiter() {
+        return ",";
+    }
+
     @Override
     public int getMaxVarcharLengthInKey() {
         return 255;