- 增加 fsql.Ado.QuerySingle(() => new {}) 扩展方法实现无表查询 SELECT now(), utc_timestamp()

Examples/base_entity/Program.cs

@@ -364,6 +364,8 @@ namespace base_entity
             public string name { get; set; }
             [Column(MapType = typeof(string))]
             public string JoinTest01Enum { get; set; }
+            [Column(MapType = typeof(int))]
+            public JoinTest01Enum JoinTest01Enum2 { get; set; }
 
             [JoinCondition("a.parentcode = b.code")]
             public JoinTest01 Parent { get; set; }
@@ -394,7 +396,7 @@ namespace base_entity
                 //.UseConnectionString(FreeSql.DataType.Firebird, @"database=localhost:D:\fbdata\EXAMPLES.fdb;user=sysdba;password=123456;max pool size=5")
 
 
-                //.UseConnectionString(FreeSql.DataType.MySql, "Data Source=127.0.0.1;Port=3306;User ID=root;Password=root;Initial Catalog=cccddd;Charset=utf8;SslMode=none;min pool size=1;Max pool size=2")
+                .UseConnectionString(FreeSql.DataType.MySql, "Data Source=127.0.0.1;Port=3306;User ID=root;Password=root;Initial Catalog=cccddd;Charset=utf8;SslMode=none;min pool size=1;Max pool size=2")
 
                 //.UseConnectionString(FreeSql.DataType.SqlServer, "Data Source=.;Integrated Security=True;Initial Catalog=freesqlTest;Pooling=true;Max Pool Size=3;TrustServerCertificate=true")
 
@@ -427,6 +429,12 @@ namespace base_entity
             BaseEntity.Initialization(fsql, () => _asyncUow.Value);
             #endregion
 
+            var result1x = fsql.Ado.QuerySingle(() => new
+            {
+                DateTime.Now,
+                DateTime.UtcNow,
+                Math.PI
+            });
 
 
             Dictionary<string, object> dic = new Dictionary<string, object>();
@@ -506,13 +514,13 @@ namespace base_entity
                         .Replace("a.", e.Tables[a].Alias + ".")
                         .Replace("b.", parentTable.Alias + ".");
                 }
-                e.Result = result;
             };
             var joinsql1 = fsql.Select<JoinTest01>()
                 .Include(a => a.Parent.Parent)
                 .Where(a => a.Parent.Parent.code == "001")
                 .Where(a => a.JoinTest01Enum == JoinTest01Enum.f3.ToString())
                 .Where(a => object.Equals(a.JoinTest01Enum, JoinTest01Enum.f3))
+                .Where(a => new[] { JoinTest01Enum.f2, JoinTest01Enum.f3 }.Contains(a.JoinTest01Enum2))
                 .ToSql();
 
 

FreeSql/Extensions/FreeSqlGlobalExtensions.cs

@@ -1228,5 +1228,41 @@ SELECT ");
 
     #endregion
 
-
+    #region Ado.QuerySingle(() => new { DateTime.Now })
+    public static T1 QuerySingle<T1>(this IAdo ado, Expression<Func<T1>> selector)
+    {
+        var nt = SelectNoTable((ado as AdoProvider)?._util._orm, selector);
+        return nt.Item1.ToListMrPrivate<T1>(nt.Item3, nt.Item2, null).FirstOrDefault();
+    }
+#if net40
+#else
+    async public static Task<T1> QuerySingleAsync<T1>(this IAdo ado, Expression<Func<T1>> selector, CancellationToken cancellationToken = default)
+    {
+        var nt = SelectNoTable((ado as AdoProvider)?._util._orm, selector);
+        var result = await nt.Item1.ToListMrPrivateAsync<T1>(nt.Item3, nt.Item2, null, cancellationToken);
+        return result.FirstOrDefault();
+    }
+#endif
+    static NativeTuple<Select1Provider<object>, ReadAnonymousTypeAfInfo, string> SelectNoTable(IFreeSql fsql, Expression selector)
+    {
+        var query = fsql.Select<object>() as Select1Provider<object>;
+        var af = query.GetExpressionField(selector);
+        var sql = "";
+        switch (fsql.Ado.DataType)
+        {
+            case DataType.Oracle:
+            case DataType.OdbcOracle:
+            case DataType.GBase:
+                sql = $" SELECT {af.field} FROM dual";
+                break;
+            case DataType.Firebird:
+                sql = $" SELECT FIRST 1 {af.field} FROM rdb$database";
+                break;
+            default:
+                sql = $" SELECT {af.field}";
+                break;
+        }
+        return NativeTuple.Create(query, af, sql);
+    }
+    #endregion
 }

FreeSql/FreeSql.xml

@@ -713,11 +713,6 @@
             天津南大通用数据技术股份有限公司成立于2004年,是国产数据库、大数据领域的知名企业，基于 Odbc 的实现
             </summary>
         </member>
-        <member name="F:FreeSql.DataType.QuestDB">
-            <summary>
-            开源时序数据库 QuestDB
-            </summary>
-        </member>
         <member name="M:FreeSql.AdoNetExtensions.GetIFreeSql(System.Data.IDbConnection)">
             <summary>
             获取 IDbConnection 对应的 IFreeSql 实例