Support TRUNC(timestamp) to make Oracle users happy.

h2/src/docsrc/help/help.csv

@@ -2799,6 +2799,7 @@ CALL HASH('SHA256', STRINGTOUTF8('Password'), 1000)
 ","
 Truncates to a number of digits (to the next value closer to 0).
 This method returns a double.
+There is also a TRUNCATE function that operates on numbers.
 ","
 TRUNCATE(VALUE, 2)
 "
@@ -3366,6 +3367,16 @@ Returns the second (0-59) from a timestamp.
 SECOND(CREATED)
 "
 
+"Functions (Time and Date)","TRUNCATE","
+{ TRUNC | TRUNCATE } (timestamp)
+","
+Truncates a timestamp to a date (day) value.
+This method returns a date.
+There is also a TRUNCATE function that operates on numbers.
+","
+TRUNCATE(CREATED)
+"
+
 "Functions (Time and Date)","WEEK","
 WEEK(timestamp)
 ","

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,7 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>-
+<ul><li>Support TRUNC(timestamp) to make Oracle users happy.
 </li></ul>
 
 <h2>Version 1.3.171 (2013-03-17)</h2>

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

@@ -204,9 +204,9 @@ public class Function extends Expression implements FunctionCall {
         addFunction("SQRT", SQRT, 1, Value.DOUBLE);
         addFunction("TAN", TAN, 1, Value.DOUBLE);
         addFunction("TANH", TANH, 1, Value.DOUBLE);
-        addFunction("TRUNCATE", TRUNCATE, 2, Value.DOUBLE);
+        addFunction("TRUNCATE", TRUNCATE, VAR_ARGS, Value.NULL);
         // same as TRUNCATE
-        addFunction("TRUNC", TRUNCATE, 2, Value.DOUBLE);
+        addFunction("TRUNC", TRUNCATE, VAR_ARGS, Value.NULL);
         addFunction("HASH", HASH, 3, Value.BYTES);
         addFunction("ENCRYPT", ENCRYPT, 3, Value.BYTES);
         addFunction("DECRYPT", DECRYPT, 3, Value.BYTES);
@@ -1016,11 +1016,22 @@ public class Function extends Expression implements FunctionCall {
             break;
         }
         case TRUNCATE: {
-            double d = v0.getDouble();
-            int p = v1.getInt();
-            double f = Math.pow(10., p);
-            double g = d * f;
-            result = ValueDouble.get(((d < 0) ? Math.ceil(g) : Math.floor(g)) / f);
+            if (v0.getType() == Value.TIMESTAMP) {
+                java.sql.Timestamp d = v0.getTimestamp();
+                Calendar c = Calendar.getInstance();
+                c.setTime(d);
+                c.set(Calendar.HOUR, 0);
+                c.set(Calendar.MINUTE, 0);
+                c.set(Calendar.SECOND, 0);
+                c.set(Calendar.MILLISECOND, 0);
+                result = ValueTimestamp.get(new java.sql.Timestamp(c.getTimeInMillis()));
+            } else {
+                double d = v0.getDouble();
+                int p = v1.getInt();
+                double f = Math.pow(10., p);
+                double g = d * f;
+                result = ValueDouble.get(((d < 0) ? Math.ceil(g) : Math.floor(g)) / f);
+            }
             break;
         }
         case HASH:
@@ -1699,6 +1710,7 @@ public class Function extends Expression implements FunctionCall {
         case FILE_READ:
         case ROUND:
         case XMLTEXT:
+        case TRUNCATE:
             min = 1;
             max = 2;
             break;
@@ -1858,11 +1870,27 @@ public class Function extends Expression implements FunctionCall {
             s = scale;
             d = displaySize;
             break;
+        case TRUNCATE:
+            t = p0.getType();
+            s = p0.getScale();
+            p = p0.getPrecision();
+            d = p0.getDisplaySize();
+            if (t == Value.NULL) {
+                t = Value.INT;
+                p = ValueInt.PRECISION;
+                d = ValueInt.DISPLAY_SIZE;
+                s = 0;
+            } else if (t == Value.TIMESTAMP) {
+                t = Value.DATE;
+                p = ValueDate.PRECISION;
+                s = 0;
+                d = ValueDate.DISPLAY_SIZE;
+            }
+            break;
         case ABS:
         case FLOOR:
         case RADIANS:
         case ROUND:
-        case TRUNCATE:
         case POWER:
             t = p0.getType();
             s = p0.getScale();
@@ -2004,6 +2032,7 @@ public class Function extends Expression implements FunctionCall {
         case TRIM:
         case STRINGDECODE:
         case UTF8TOSTRING:
+        case TRUNCATE:
             precision = args[0].getPrecision();
             displaySize = args[0].getDisplaySize();
             break;

h2/src/main/org/h2/res/help.csv

@@ -1223,6 +1223,10 @@ Returns the quarter (1-4) from a timestamp."
 SECOND(timestamp)
 ","
 Returns the second (0-59) from a timestamp."
+"Functions (Time and Date)","TRUNCATE","
+TRUNCATE(timestamp)
+","
+Truncates a timestamp to a date (day) value."
 "Functions (Time and Date)","WEEK","
 WEEK(timestamp)
 ","

h2/src/main/org/h2/value/ValueDate.java

@@ -29,7 +29,7 @@ public class ValueDate extends Value {
      * The display size of the textual representation of a date.
      * Example: 2000-01-02
      */
-    static final int DISPLAY_SIZE = 10;
+    public static final int DISPLAY_SIZE = 10;
 
     private final long dateValue;
 

h2/src/test/org/h2/test/TestBase.java

@@ -25,9 +25,11 @@ import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.sql.Types;
+import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.LinkedList;
+import java.util.SimpleTimeZone;
 import org.h2.jdbc.JdbcConnection;
 import org.h2.message.DbException;
 import org.h2.message.TraceSystem;
@@ -589,6 +591,22 @@ public abstract class TestBase {
         }
     }
 
+    /**
+     * Check if two values are equal, and if not throw an exception.
+     *
+     * @param expected the expected value
+     * @param actual the actual value
+     * @throws AssertionError if the values are not equal
+     */
+    public void assertEquals(java.util.Date expected, java.util.Date actual) {
+        if (expected != actual && !expected.equals(actual)) {
+            final DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
+            final SimpleTimeZone GMT_TIMEZONE = new SimpleTimeZone(0, "Z");
+            df.setTimeZone(GMT_TIMEZONE);
+            fail("Expected: " + df.format(expected) + " actual: " + df.format(actual));
+        }
+    }
+    
     /**
      * Check if two values are equal, and if not throw an exception.
      *

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

@@ -17,6 +17,7 @@ import java.sql.CallableStatement;
 import java.sql.Clob;
 import java.sql.Connection;
 import java.sql.DatabaseMetaData;
+import java.sql.Date;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
@@ -25,6 +26,7 @@ import java.sql.SQLException;
 import java.sql.Statement;
 import java.sql.Types;
 import java.util.ArrayList;
+import java.util.Calendar;
 import java.util.Properties;
 import java.util.UUID;
 import org.h2.api.AggregateFunction;
@@ -75,6 +77,7 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         testValue();
         testNvl2();
         testConcatWs();
+        testTruncate();
         deleteDb("functions");
         FileUtils.deleteRecursive(TEMP_DIR, true);
     }
@@ -860,6 +863,46 @@ public class TestFunctions extends TestBase implements AggregateFunction {
         conn.close();
     }
 
+    private void testTruncate() throws SQLException {
+        deleteDb("functions");
+        Connection conn = getConnection("functions");
+        Statement stat = conn.createStatement();
+        
+        ResultSet rs = stat.executeQuery("SELECT TRUNCATE(1.234, 2) FROM dual");
+        rs.next();
+        assertEquals(1.23d, rs.getDouble(1));
+        
+        rs = stat.executeQuery("SELECT CURRENT_TIMESTAMP(), TRUNCATE(CURRENT_TIMESTAMP()) FROM dual");
+        rs.next();
+        Calendar c = Calendar.getInstance();
+        c.setTime(rs.getTimestamp(1));
+        c.set(Calendar.HOUR, 0);
+        c.set(Calendar.MINUTE, 0);
+        c.set(Calendar.SECOND, 0);
+        c.set(Calendar.MILLISECOND, 0);
+        java.util.Date nowDate = c.getTime();
+        assertEquals(nowDate, rs.getTimestamp(2));
+        
+        try {
+            rs = stat.executeQuery("SELECT TRUNCATE('bad', 1) FROM dual");
+            fail("expected exception");
+        } catch (SQLException ex) {}
+        
+        // check for passing wrong data type
+        try {
+            rs = stat.executeQuery("SELECT TRUNCATE('bad') FROM dual");
+            fail("expected exception");
+        } catch (SQLException ex) {}
+        
+        // check for too many parameters
+        try {
+            rs = stat.executeQuery("SELECT TRUNCATE(1,2,3) FROM dual");
+            fail("expected exception");
+        } catch (SQLException ex) {}
+        
+        conn.close();
+    }
+    
     private void assertCallResult(String expected, Statement stat, String sql) throws SQLException {
         ResultSet rs = stat.executeQuery("CALL " + sql);
         rs.next();