Merge pull request #541 from mnsrulz/master

allow select without table to support cross apply

Author: ahmad-moussawi

QueryBuilder.Tests/SelectTests.cs

@@ -814,5 +814,24 @@ public void EscapeClauseThrowsForMultipleCharacters()
                     .HavingContains("Column1", @"TestString\%", false, @"\aa");
             });
         }
+
+
+        [Fact]
+        public void BasicSelectRaw_WithNoTable()
+        {
+            var q = new Query().SelectRaw("somefunction() as c1");                
+
+            var c = Compilers.CompileFor(EngineCodes.SqlServer, q);
+            Assert.Equal("SELECT somefunction() as c1", c.ToString());
+        }
+
+        [Fact]
+        public void BasicSelect_WithNoTable()
+        {
+            var q = new Query().Select("c1");
+            var c = Compilers.CompileFor(EngineCodes.SqlServer, q);
+            Assert.Equal("SELECT [c1]", c.ToString());
+        }
+        
     }
 }

QueryBuilder/Compilers/Compiler.cs

@@ -647,14 +647,14 @@ public virtual string CompileTableExpression(SqlResult ctx, AbstractFrom from)
 
         public virtual string CompileFrom(SqlResult ctx)
         {
-            if (!ctx.Query.HasComponent("from", EngineCode))
+            if (ctx.Query.HasComponent("from", EngineCode))
             {
-                throw new InvalidOperationException("No table is set");
-            }
+                var from = ctx.Query.GetOneComponent<AbstractFrom>("from", EngineCode);
 
-            var from = ctx.Query.GetOneComponent<AbstractFrom>("from", EngineCode);
+                return "FROM " + CompileTableExpression(ctx, from);
+            }
 
-            return "FROM " + CompileTableExpression(ctx, from);
+            return string.Empty;
         }
 
         public virtual string CompileJoins(SqlResult ctx)