Add random() order support

src/OrchardCore.Modules/OrchardCore.Queries/Sql/SqlGrammar.cs

@@ -146,7 +146,7 @@ public SqlGrammar() : base(false)
 
         // Create Index.
         orderList.Rule = MakePlusRule(orderList, comma, orderMember);
-        orderMember.Rule = Id + orderDirOptional;
+        orderMember.Rule = Id + (orderDirOptional | "(" + functionArguments + ")");
         orderDirOptional.Rule = Empty | "ASC" | "DESC";
 
         // Select stmt.

src/OrchardCore.Modules/OrchardCore.Queries/Sql/SqlParser.cs

@@ -246,20 +246,36 @@ private void EvaluateOrderClause(ParseTreeNode parseTreeNode)
         var idList = parseTreeNode.ChildNodes[2];
 
         _modes.Push(FormattingModes.SelectClause);
+
         for (var i = 0; i < idList.ChildNodes.Count; i++)
         {
-            var id = idList.ChildNodes[i].ChildNodes[0];
-
             if (i > 0)
             {
                 _builder.Append(", ");
             }
 
+            var id = idList.ChildNodes[i].ChildNodes[0];
+
+            // RANDOM() is a special case where we need to use the dialect's random function.
+            if (id.ChildNodes[0].Token?.ValueString == "RANDOM")
+            {
+                var funArgs = idList.ChildNodes[i].ChildNodes[1].ChildNodes[0];
+
+                // "RANDOM" + {funArgs} + no arguments?
+                if (funArgs.Term.Name == "funArgs" && funArgs.ChildNodes.Count == 0)
+                {
+                    _builder.Append(_dialect.RandomOrderByClause);
+                    continue;
+                }
+            }
+
             EvaluateId(id);
 
-            if (idList.ChildNodes[i].ChildNodes[1].ChildNodes.Count > 0)
+            var orderDirOpt = idList.ChildNodes[i].ChildNodes[1].ChildNodes[0];
+
+            if (orderDirOpt.Term.Name == "orderDirOpt" && orderDirOpt.ChildNodes.Count > 0)
             {
-                _builder.Append(' ').Append(idList.ChildNodes[i].ChildNodes[1].ChildNodes[0].Term.Name);
+                _builder.Append(' ').Append(orderDirOpt.ChildNodes[0].Term.Name);
             }
         }
 
@@ -805,7 +821,7 @@ private void EvaluateOverClauseOptional(ParseTreeNode overClauseOpt)
                 var orderMember = orderList.ChildNodes[i];
                 var id = orderMember.ChildNodes[0];
                 EvaluateSelectId(id);
-                var orderDirOpt = orderMember.ChildNodes[1];
+                var orderDirOpt = orderMember.ChildNodes[1].ChildNodes[0];
                 if (orderDirOpt.ChildNodes.Count > 0)
                 {
                     _builder.Append(' ').Append(orderDirOpt.ChildNodes[0].Term.Name);

src/docs/reference/modules/Queries/README.md

@@ -289,6 +289,12 @@ The SQL parser is also able to convert some specific functions to the intended d
 | `year(_date_)`   | Returns the years part of a date.   |
 | `now()`          | Returns current date time (utc).    |
 
+Order By clauses can also use the `random()` function (case insensitive) to order results randomly, e.g., 
+
+```
+SELECT * FROM ContentItemIndex ORDER BY random()
+```
+
 ## Scripting
 
 The following JavaScript functions are available with this module.

test/OrchardCore.Tests/Orchard.Queries/SqlParserTests.cs

@@ -243,4 +243,15 @@ public void ShouldParseSubquery(string sql, string expectedSql)
         Assert.True(result);
         Assert.Equal(expectedSql, FormatSql(rawQuery));
     }
+
+    [Theory]
+    [InlineData("select a order by RANDOM()", "SELECT [a] ORDER BY newid();")]
+    [InlineData("select a order by random()", "SELECT [a] ORDER BY newid();")]
+    [InlineData("select a order by RANDOM", "SELECT [a] ORDER BY [RANDOM];")]
+    public void ShouldOrderByRandom(string sql, string expectedSql)
+    {
+        var result = SqlParser.TryParse(sql, _schema, _defaultDialect, _defaultTablePrefix, null, out var rawQuery, out var errors);
+        Assert.True(result);
+        Assert.Equal(expectedSql, FormatSql(rawQuery));
+    }
 }