Apply #418: MySQL compatibility: support for ALTER TABLE tbl_name MODIFY…

Apply #418: MySQL compatibility: support for ALTER TABLE tbl_name MODIFY [COLUMN] col_name column_definition, patch from Ville Koskela.

h2/src/docsrc/html/changelog.html

@@ -63,6 +63,7 @@ Change Log
 </li><li>Experimental off-heap memory storage engine "nioMemFS:" and "nioMemLZF:",
     suggestion from Mark Addleman.
 </li><li>Fix issue #438:JdbcDatabaseMetaData#getSchemas() no longer supported as of 1.3.169
+</li><li>MySQL compatibility: support for ALTER TABLE tbl_name MODIFY [COLUMN] col_name column_definition, patch from Ville Koskela.
 </li></ul>
 
 <h2>Version 1.3.170 (2012-11-30)</h2>

h2/src/main/org/h2/command/Parser.java

@@ -4878,6 +4878,12 @@ public class Parser {
                 command.setOldColumn(table.getColumn(columnName));
                 return command;
             }
+        } else if (readIf("MODIFY")) {
+            // MySQL compatibility
+            readIf("COLUMN");
+            String columnName = readColumnIdentifier();
+            Column column = table.getColumn(columnName);
+            return parseAlterTableAlterColumnType(table, columnName, column);
         } else if (readIf("ALTER")) {
             readIf("COLUMN");
             String columnName = readColumnIdentifier();

h2/src/test/org/h2/test/db/TestAlter.java

@@ -45,6 +45,7 @@ public class TestAlter extends TestBase {
         testAlterTableAlterColumn2();
         testAlterTableAddColumnBefore();
         testAlterTableAddColumnAfter();
+        testAlterTableModifyColumn();
         conn.close();
         deleteDb("alter");
     }
@@ -186,4 +187,10 @@ public class TestAlter extends TestBase {
         stat.execute("drop table t");
     }
 
+    private void testAlterTableModifyColumn() throws SQLException {
+        stat.execute("create table t(x int)");
+        stat.execute("alter table t modify column x varchar(20)");
+        stat.execute("insert into t values('Hello')");
+        stat.execute("drop table t");
+    }
 }