ALTER TABLE ALTER COLUMN DROP DEFAULT is a part of standard

h2/src/docsrc/help/help.csv

@@ -355,11 +355,12 @@ ALTER TABLE [ IF EXISTS ] tableName ALTER COLUMN columnName
     | { RESTART WITH long }
     | { SELECTIVITY int }
     | { SET DEFAULT expression }
+    | { DROP DEFAULT }
     | { SET ON UPDATE expression }
     | { SET NULL }
     | { SET NOT NULL }
     | { SET { VISIBLE | INVISIBLE } }
-    | { DROP { DEFAULT | ON UPDATE } } }
+    | { DROP ON UPDATE } }
 ","
 Changes the data type of a column, rename a column,
 change the identity value, or change the selectivity.
@@ -377,6 +378,8 @@ Selectivity 100 means values are unique, 10 means every distinct value appears 1
 
 SET DEFAULT changes the default value of a column.
 
+DROP DEFAULT removes the default value of a column.
+
 SET ON UPDATE changes the value that is set on update if value for this column is not specified in update statement.
 
 SET NULL sets a column to allow NULL. The row may not be part of a primary key.
@@ -387,8 +390,6 @@ SET NOT NULL sets a column to not allow NULL. Rows may not contains NULL in this
 SET INVISIBLE makes the column hidden, i.e. it will not appear in SELECT * results.
 SET VISIBLE has the reverse effect.
 
-DROP DEFAULT removes the default value of a column.
-
 DROP ON UPDATE removes the value that is set on update of a column.
 
 This command commits an open transaction in this connection.

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

@@ -68,7 +68,8 @@ public interface CommandInterface {
     int ALTER_TABLE_ALTER_COLUMN_NULL = 9;
 
     /**
-     * The type of a ALTER TABLE ALTER COLUMN SET DEFAULT statement.
+     * The type of a ALTER TABLE ALTER COLUMN SET DEFAULT and ALTER TABLE ALTER
+     * COLUMN DROP DEFAULT statements.
      */
     int ALTER_TABLE_ALTER_COLUMN_DEFAULT = 10;
 

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

@@ -7247,10 +7247,8 @@ public class Parser {
                 command.setNewColumnName(newName);
                 return command;
             } else if (readIf("DROP")) {
-                // PostgreSQL compatibility
                 if (readIf("DEFAULT")) {
-                    AlterTableAlterColumn command = new AlterTableAlterColumn(
-                            session, schema);
+                    AlterTableAlterColumn command = new AlterTableAlterColumn(session, schema);
                     command.setTableName(tableName);
                     command.setIfTableExists(ifTableExists);
                     command.setOldColumn(column);

h2/src/test/org/h2/test/scripts/TestScript.java

@@ -152,9 +152,9 @@ public class TestScript extends TestDb {
                 "uuid", "varchar", "varchar-ignorecase" }) {
             testScript("datatypes/" + s + ".sql");
         }
-        for (String s : new String[] { "alterTableAdd", "alterTableDropColumn", "alterTableRename",
-                "createAlias", "createSequence", "createSynonym", "createTable", "createTrigger", "createView",
-                "dropDomain", "dropIndex", "dropSchema", "truncateTable" }) {
+        for (String s : new String[] { "alterTableAdd", "alterTableAlterColumn", "alterTableDropColumn",
+                "alterTableRename", "createAlias", "createSequence", "createSynonym", "createTable", "createTrigger",
+                "createView", "dropDomain", "dropIndex", "dropSchema", "truncateTable" }) {
             testScript("ddl/" + s + ".sql");
         }
         for (String s : new String[] { "delete", "error_reporting", "insert", "insertIgnore", "merge", "mergeUsing",

h2/src/test/org/h2/test/scripts/ddl/alterTableAlterColumn.sql

+-- Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
+-- and the EPL 1.0 (http://h2database.com/html/license.html).
+-- Initial Developer: H2 Group
+--
+
+CREATE TABLE TEST(T INT);
+> ok
+
+SELECT COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME = 'T';
+>> INT
+
+-- SET DEFAULT
+ALTER TABLE TEST ALTER COLUMN T SET DEFAULT 1;
+> ok
+
+SELECT COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME = 'T';
+>> INT DEFAULT 1
+
+-- DROP DEFAULT
+ALTER TABLE TEST ALTER COLUMN T DROP DEFAULT;
+> ok
+
+SELECT COLUMN_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME = 'T';
+>> INT
+
+DROP TABLE TEST;
+> ok