Fix Issue 406: support "SELECT h2version()"

h2/src/docsrc/help/help.csv

@@ -3837,6 +3837,14 @@ Returns the name of the current user of this session.
 CURRENT_USER()
 "
 
+"Functions (System)","H2VERSION","
+H2VERSION()
+","
+Returns the H2 version as a String.
+","
+H2VERSION()
+"
+
 "System Tables","Information Schema","
 INFORMATION_SCHEMA
 ","

h2/src/docsrc/html/changelog.html

@@ -27,6 +27,7 @@ Change Log
 </li><li>Add new collation command SET BINARY_COLLATION UNSIGNED, helps with people testing BINARY columns in MySQL mode.
 </li><li>Fix issue #453, ABBA race conditions in TABLE LINK connection sharing.
 </li><li>Fix Issue 449: Postgres Serial data type should not automatically be marked as primary key
+</li><li>Fix Issue 406: support "SELECT h2version()"
 </li></ul>
 
 <h2>Version 1.3.171 (2013-03-17)</h2>

h2/src/main/org/h2/expression/Function.java

@@ -26,6 +26,7 @@ import java.util.regex.PatternSyntaxException;
 import org.h2.command.Command;
 import org.h2.command.Parser;
 import org.h2.constant.ErrorCode;
+import org.h2.engine.Constants;
 import org.h2.engine.Database;
 import org.h2.engine.Mode;
 import org.h2.engine.Session;
@@ -101,6 +102,12 @@ public class Function extends Expression implements FunctionCall {
             LINK_SCHEMA = 218, GREATEST = 219, LEAST = 220, CANCEL_SESSION = 221, SET = 222, TABLE = 223, TABLE_DISTINCT = 224,
             FILE_READ = 225, TRANSACTION_ID = 226, TRUNCATE_VALUE = 227, NVL2 = 228, DECODE = 229, ARRAY_CONTAINS = 230;
 
+    /**
+     * This is called H2VERSION() and not VERSION(), because we return a fake value
+     * for VERSION() when running under the PostgreSQL ODBC driver.
+     */
+    public static final int H2VERSION = 231;
+
     public static final int ROW_NUMBER = 300;
 
     private static final int VAR_ARGS = -1;
@@ -346,6 +353,7 @@ public class Function extends Expression implements FunctionCall {
         addFunctionNotDeterministic("TRANSACTION_ID", TRANSACTION_ID, 0, Value.STRING);
         addFunctionWithNull("DECODE", DECODE, VAR_ARGS, Value.NULL);
         addFunctionNotDeterministic("DISK_SPACE_USED", DISK_SPACE_USED, 1, Value.LONG);
+        addFunction("H2VERSION", H2VERSION, 0, Value.STRING);
 
         // TableFunction
         addFunctionWithNull("TABLE", TABLE, VAR_ARGS, Value.RESULT_SET);
@@ -1138,6 +1146,9 @@ public class Function extends Expression implements FunctionCall {
         case LPAD:
             result = ValueString.get(StringUtils.pad(v0.getString(), v1.getInt(), v2 == null ? null : v2.getString(), false));
             break;
+        case H2VERSION:
+            result = ValueString.get(Constants.getVersion());
+            break;
         case DATE_ADD:
             result = ValueTimestamp.get(dateadd(v0.getString(), v1.getInt(), v2.getTimestamp()));
             break;

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

@@ -31,6 +31,7 @@ import java.util.Properties;
 import java.util.UUID;
 import org.h2.api.AggregateFunction;
 import org.h2.constant.ErrorCode;
+import org.h2.engine.Constants;
 import org.h2.store.fs.FileUtils;
 import org.h2.test.TestBase;
 import org.h2.tools.SimpleResultSet;
@@ -56,6 +57,7 @@ public class TestFunctions extends TestBase implements AggregateFunction {
 
     public void test() throws Exception {
         deleteDb("functions");
+        testVersion();
         testFunctionTable();
         testArrayParameters();
         testDefaultConnection();
@@ -82,6 +84,20 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         FileUtils.deleteRecursive(TEMP_DIR, true);
     }
 
+    private void testVersion() throws SQLException {
+        Connection conn = getConnection("functions");
+        Statement stat = conn.createStatement();
+        String query = "select h2version()";
+        ResultSet rs = stat.executeQuery(query);
+        assertTrue(rs.next());
+        String version = rs.getString(1);
+        assertEquals(Constants.getVersion(), version);
+        assertFalse(rs.next());
+        rs.close();
+        stat.close();
+        conn.close();
+    }
+
     private void testFunctionTable() throws SQLException {
         Connection conn = getConnection("functions");
         Statement stat = conn.createStatement();