Function alias

Author: gliljas

src/NHibernate/Dialect/Function/SQLFunctionRegistry.cs

@@ -7,6 +7,7 @@ public class SQLFunctionRegistry
 	{
 		private readonly Dialect dialect;
 		private readonly IDictionary<string, ISQLFunction> userFunctions;
+		private static Dictionary<string,string> _functionAliases = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase) {{"secondtruncated","second"}};
 
 		public SQLFunctionRegistry(Dialect dialect, IDictionary<string, ISQLFunction> userFunctions)
 		{
@@ -21,16 +22,15 @@ public SQLFunctionRegistry(Dialect dialect, IDictionary<string, ISQLFunction> us
 		public ISQLFunction FindSQLFunction(string functionName)
 		{
 			ISQLFunction result;
-			if (!userFunctions.TryGetValue(functionName, out result))
+			if (!userFunctions.TryGetValue(functionName, out result) && !dialect.Functions.TryGetValue(functionName, out result) && _functionAliases.TryGetValue(functionName, out var aliased) && dialect.Functions.TryGetValue(aliased, out result))
 			{
-				dialect.Functions.TryGetValue(functionName, out result);
 			}
 			return result;
 		}
 
 		public bool HasFunction(string functionName)
 		{
-			return userFunctions.ContainsKey(functionName) || dialect.Functions.ContainsKey(functionName);
+			return userFunctions.ContainsKey(functionName) || dialect.Functions.ContainsKey(functionName) || _functionAliases.TryGetValue(functionName, out var aliased) && dialect.Functions.ContainsKey(aliased);
 		}
 	}
 }

src/NHibernate/Linq/Functions/DateTimePropertiesHqlGenerator.cs

@@ -35,7 +35,7 @@ public DateTimePropertiesHqlGenerator()
 		public override HqlTreeNode BuildHql(MemberInfo member, Expression expression, HqlTreeBuilder treeBuilder, IHqlExpressionVisitor visitor)
 		{
 			var functionName = member.Name.ToLowerInvariant();
-			if (functionName == "second" && (visitor.SessionFactory as ISessionFactoryImplementor)?.Dialect.Functions.ContainsKey("secondtruncated") == true)
+			if (functionName == "second")
 			{
 				functionName = "secondtruncated";
 			}