Merge pull request #948 from katzyn/ddl

Fix some grammar descriptions and ALTER TABLE DROP COLUMN parsing

h2/src/docsrc/help/help.csv

@@ -227,9 +227,8 @@ SHOW TABLES
 "
 
 "Commands (DML)","WITH","
-WITH [ RECURSIVE ] { name [( columnName [,...] )]
-    AS ( select ) [,...] }
-    { select | insert | update | merge | delete | createTable }
+WITH [ RECURSIVE ] { name [( columnName [,...] )] AS ( select ) [,...] }
+{ select | insert | update | merge | delete | createTable }
 ","
 Can be used to create a recursive or non-recursive query (common table expression).
 For recursive queries the first select has to be a UNION.
@@ -373,13 +372,14 @@ ALTER TABLE TEST ALTER COLUMN NAME SET INVISIBLE;
 
 "Commands (DDL)","ALTER TABLE DROP COLUMN","
 ALTER TABLE [ IF EXISTS ] tableName DROP COLUMN [ IF EXISTS ]
-( columnName [,...] )
+columnName [,...] | ( columnName [,...] )
 ","
 Removes column(s) from a table.
 This command commits an open transaction in this connection.
 ","
 ALTER TABLE TEST DROP COLUMN NAME
 ALTER TABLE TEST DROP COLUMN NAME1, NAME2
+ALTER TABLE TEST DROP COLUMN (NAME1, NAME2)
 "
 
 "Commands (DDL)","ALTER TABLE DROP CONSTRAINT","
@@ -394,7 +394,7 @@ ALTER TABLE TEST DROP CONSTRAINT UNIQUE_NAME
 
 "Commands (DDL)","ALTER TABLE SET","
 ALTER TABLE [ IF EXISTS ] tableName SET REFERENTIAL_INTEGRITY
-    { FALSE | TRUE [ CHECK | NOCHECK ] }
+{ FALSE | TRUE } [ CHECK | NOCHECK ]
 ","
 Disables or enables referential integrity checking for a table. This command can
 be used inside a transaction. Enabling referential integrity does not check

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

@@ -6103,28 +6103,28 @@ public class Parser {
             } else {
                 readIf("COLUMN");
                 boolean ifExists = readIfExists(false);
-                AlterTableAlterColumn command = new AlterTableAlterColumn(
-                        session, schema);
-                command.setType(CommandInterface.ALTER_TABLE_DROP_COLUMN);
                 ArrayList<Column> columnsToRemove = New.arrayList();
                 Table table = tableIfTableExists(schema, tableName, ifTableExists);
                 // For Oracle compatibility - open bracket required
                 boolean openingBracketDetected = readIf("(");
                 do {
                     String columnName = readColumnIdentifier();
-                    if (table == null) {
-                        return new NoOperation(session);
-                    }
-                    if (ifExists && !table.doesColumnExist(columnName)) {
-                        return new NoOperation(session);
+                    if (table != null) {
+                        if (!ifExists || table.doesColumnExist(columnName)) {
+                            Column column = table.getColumn(columnName);
+                            columnsToRemove.add(column);
+                        }
                     }
-                    Column column = table.getColumn(columnName);
-                    columnsToRemove.add(column);
                 } while (readIf(","));
                 if (openingBracketDetected) {
                     // For Oracle compatibility - close bracket
                     read(")");
                 }
+                if (table == null || columnsToRemove.isEmpty()) {
+                    return new NoOperation(session);
+                }
+                AlterTableAlterColumn command = new AlterTableAlterColumn(session, schema);
+                command.setType(CommandInterface.ALTER_TABLE_DROP_COLUMN);
                 command.setTableName(tableName);
                 command.setIfTableExists(ifTableExists);
                 command.setColumnsToRemove(columnsToRemove);

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

@@ -101,7 +101,7 @@ public class TestScript extends TestBase {
                 "uuid", "varchar", "varchar-ignorecase" }) {
             testScript("datatypes/" + s + ".sql");
         }
-        for (String s : new String[] { "alterTableAdd", "createView", "dropSchema" }) {
+        for (String s : new String[] { "alterTableAdd", "alterTableDropColumn", "createView", "dropSchema" }) {
             testScript("ddl/" + s + ".sql");
         }
         for (String s : new String[] { "insertIgnore", "mergeUsing", "script", "with" }) {

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

+-- Copyright 2004-2018 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(A VARCHAR, B VARCHAR, C VARCHAR AS LOWER(A));
+> ok
+
+ALTER TABLE TEST DROP COLUMN B;
+> ok
+
+DROP TABLE TEST;
+> ok
+
+ALTER TABLE IF EXISTS TEST DROP COLUMN A;
+> ok
+
+ALTER TABLE TEST DROP COLUMN A;
+> exception
+
+CREATE TABLE TEST(A INT, B INT, C INT, D INT, E INT, F INT, G INT, H INT, I INT, J INT);
+> ok
+
+ALTER TABLE TEST DROP COLUMN IF EXISTS J;
+> ok
+
+ALTER TABLE TEST DROP COLUMN J;
+> exception
+
+ALTER TABLE TEST DROP COLUMN B;
+> ok
+
+ALTER TABLE TEST DROP COLUMN IF EXISTS C;
+> ok
+
+SELECT * FROM TEST;
+> A D E F G H I
+> - - - - - - -
+> rows: 0
+
+ALTER TABLE TEST DROP COLUMN B, D;
+> exception
+
+ALTER TABLE TEST DROP COLUMN IF EXISTS B, D;
+> ok
+
+SELECT * FROM TEST;
+> A E F G H I
+> - - - - - -
+> rows: 0
+
+ALTER TABLE TEST DROP COLUMN E, F;
+> ok
+
+SELECT * FROM TEST;
+> A G H I
+> - - - -
+> rows: 0
+
+ALTER TABLE TEST DROP COLUMN (B, H);
+> exception
+
+ALTER TABLE TEST DROP COLUMN IF EXISTS (B, H);
+> ok
+
+SELECT * FROM TEST;
+> A G I
+> - - -
+> rows: 0
+
+ALTER TABLE TEST DROP COLUMN (G, I);
+> ok
+
+SELECT * FROM TEST;
+> A
+> -
+> rows: 0
+
+DROP TABLE TEST;
+> ok

h2/src/test/org/h2/test/scripts/testScript.sql

@@ -2241,15 +2241,6 @@ select * from (select 1), (select 2);
 > 1 2
 > rows: 1
 
-CREATE TABLE TEST(A VARCHAR, B VARCHAR, C VARCHAR AS LOWER(A));
-> ok
-
-ALTER TABLE TEST DROP COLUMN B;
-> ok
-
-DROP TABLE TEST;
-> ok
-
 create table t1(c1 int, c2 int);
 > ok