#116 added datediff and dateadd support

querydsl-scala/src/main/scala/com/mysema/query/scala/package.scala

@@ -48,7 +48,10 @@ package object scala {
     implicit val bigDecimal = new Numeric[java.math.BigDecimal]
     implicit val bigInteger = new Numeric[java.math.BigInteger]
   }
-
+
+  /**
+   * Type class for Number types
+   */
   class Numeric[Num]
 
 } 

querydsl-sql/src/main/java/com/mysema/query/sql/mssql/DatePart.java

@@ -0,0 +1,17 @@
+package com.mysema.query.sql.mssql;
+
+public enum DatePart {
+    year,
+    quarter,
+    month,
+    dayofyear,
+    day,
+    week,
+    hour,
+    minute,
+    second,
+    millisecond,
+    microsecond,
+    nanosecond
+
+}

querydsl-sql/src/main/java/com/mysema/query/sql/mssql/SQLServerGrammar.java

@@ -13,8 +13,14 @@
  */
 package com.mysema.query.sql.mssql;
 
+import com.mysema.query.types.Constant;
+import com.mysema.query.types.ConstantImpl;
+import com.mysema.query.types.Template;
+import com.mysema.query.types.TemplateFactory;
+import com.mysema.query.types.expr.DateExpression;
 import com.mysema.query.types.expr.NumberExpression;
 import com.mysema.query.types.path.NumberPath;
+import com.mysema.query.types.template.DateTemplate;
 import com.mysema.query.types.template.NumberTemplate;
 
 /**
@@ -25,6 +31,10 @@
  */
 public final class SQLServerGrammar {
 
+    private static final Template DATEDIFF = TemplateFactory.DEFAULT.create("datediff('{0s}',{1},{2})");
+
+    private static final Template DATEADD = TemplateFactory.DEFAULT.create("dateadd('{0s}',{1},{2})");
+
     private SQLServerGrammar() {}
 
     public static final NumberExpression<Long> rowNumber = NumberTemplate.create(Long.class, "row_number");
@@ -34,5 +44,17 @@ private SQLServerGrammar() {}
     public static RowNumber rowNumber() {
         return new RowNumber();
     }
-
+
+    private static final <T> Constant<T> constant(T constant) {
+        return new ConstantImpl<T>(constant);
+    }
+
+    public static <D> NumberExpression<Integer> datediff(DatePart datePart, D start, D end) {
+        return NumberTemplate.create(Integer.class, DATEDIFF, constant(datePart.name()), constant(start), constant(end));
+    }
+
+    public static <D extends Comparable<D>> DateExpression<D> dateadd(DatePart datePart, int num, D date) {
+        return DateTemplate.<D>create((Class<D>)date.getClass(), DATEADD, constant(datePart.name()), constant(num), constant(date));
+    }
+
 }

querydsl-sql/src/test/java/com/mysema/query/_mssql/SQLServerGrammarTest.java

@@ -0,0 +1,24 @@
+package com.mysema.query._mssql;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.mysema.query.sql.mssql.DatePart;
+import com.mysema.query.sql.mssql.SQLServerGrammar;
+
+public class SQLServerGrammarTest {
+
+    @Test
+    public void Datediff() {
+        assertEquals("datediff('day',start,end)", 
+                SQLServerGrammar.datediff(DatePart.day, "start", "end").toString());
+    }
+
+    @Test
+    public void Dateadd() {
+        assertEquals("dateadd('hour',3,start)", 
+                SQLServerGrammar.dateadd(DatePart.hour, 3, "start").toString());
+    }
+
+}