- 增加 MySq 表达式解析 yyyyMMdd 常用 c# 日期格式化；

FreeSql.Tests/FreeSql.Tests.Provider.MySqlConnector/MySqlConnector/MySqlConnectorExpression/DateTimeTest.cs

@@ -41,6 +41,43 @@ namespace FreeSql.Tests.MySqlConnectorExpression
             public List<TestTypeInfo> Types { get; set; }
             public DateTime Time2 { get; set; }
         }
+
+        [Fact]
+        public void this_ToString()
+        {
+            var data = new List<object>();
+            data.Add(select.Where(a => a.CreateTime.ToString().Equals(DateTime.Now)).ToList());
+            data.Add(select.Where(a => a.Type.Time.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
+            data.Add(select.Where(a => a.Type.Parent.Time2.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a.`Title` as4, a.`CreateTime` as5 
+            //FROM `tb_topic111333` a 
+            //WHERE ((date_format(a.`CreateTime`, '%Y-%m-%d %H:%i:%s.%f') = now()));
+
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
+            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type 
+            //WHERE ((date_format(date_add(a__Type.`Time`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()));
+
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
+            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
+            //WHERE ((date_format(date_add(a__Type__Parent.`Time2`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()))
+
+            g.mysql.Insert(new Topic()).ExecuteAffrows();
+            foreach (var dt in new[] { DateTime.Parse("2020-5-6 0:1:2"), DateTime.Parse("2020-11-16 13:21:22"), })
+            {
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm:ss.ffffff"), select.First(a => dt.ToString()));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm:ss"), select.First(a => dt.ToString("yyyy-MM-dd HH:mm:ss")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm"), select.First(a => dt.ToString("yyyy-MM-dd HH:mm")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH"), select.First(a => dt.ToString("yyyy-MM-dd HH")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd"), select.First(a => dt.ToString("yyyy-MM-dd")));
+                Assert.Equal(dt.ToString("yyyy-MM"), select.First(a => dt.ToString("yyyy-MM")));
+                Assert.Equal(dt.ToString("yyyyMMdd"), select.First(a => dt.ToString("yyyyMMdd")));
+                Assert.Equal(dt.ToString("yyyyMM"), select.First(a => dt.ToString("yyyyMM")));
+                Assert.Equal(dt.ToString("yyyy"), select.First(a => dt.ToString("yyyy")));
+                Assert.Equal(dt.ToString("HH:mm:ss"), select.First(a => dt.ToString("HH:mm:ss")));
+                Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h")));
+                Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t").Replace("ÉÏÎç", "AM").Replace("ÏÂÎç", "PM").Replace("ÉÏ", "A").Replace("ÏÂ", "P"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t")));
+            }
+        }
         [Fact]
         public void Now()
         {
@@ -542,26 +579,6 @@ namespace FreeSql.Tests.MySqlConnectorExpression
             //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
             //WHERE ((date_add(a__Type__Parent.`Time2`, interval (1) year) = now()))
         }
-        [Fact]
-        public void this_ToString()
-        {
-            var data = new List<object>();
-            data.Add(select.Where(a => a.CreateTime.ToString().Equals(DateTime.Now)).ToList());
-            data.Add(select.Where(a => a.Type.Time.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
-            data.Add(select.Where(a => a.Type.Parent.Time2.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a.`Title` as4, a.`CreateTime` as5 
-            //FROM `tb_topic111333` a 
-            //WHERE ((date_format(a.`CreateTime`, '%Y-%m-%d %H:%i:%s.%f') = now()));
-
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
-            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type 
-            //WHERE ((date_format(date_add(a__Type.`Time`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()));
-
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
-            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
-            //WHERE ((date_format(date_add(a__Type__Parent.`Time2`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()))
-        }
-
         [Fact]
         public void DateTime_Compare()
         {

FreeSql.Tests/FreeSql.Tests.Provider.Odbc/MySql/MySqlExpression/DateTimeTest.cs

@@ -41,6 +41,43 @@ namespace FreeSql.Tests.Odbc.MySqlExpression
             public List<TestTypeInfo> Types { get; set; }
             public DateTime Time2 { get; set; }
         }
+
+        [Fact]
+        public void this_ToString()
+        {
+            var data = new List<object>();
+            data.Add(select.Where(a => a.CreateTime.ToString().Equals(DateTime.Now)).ToList());
+            data.Add(select.Where(a => a.Type.Time.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
+            data.Add(select.Where(a => a.Type.Parent.Time2.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a.`Title` as4, a.`CreateTime` as5 
+            //FROM `tb_topic111333` a 
+            //WHERE ((date_format(a.`CreateTime`, '%Y-%m-%d %H:%i:%s.%f') = now()));
+
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
+            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type 
+            //WHERE ((date_format(date_add(a__Type.`Time`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()));
+
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
+            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
+            //WHERE ((date_format(date_add(a__Type__Parent.`Time2`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()))
+
+            g.mysql.Insert(new Topic()).ExecuteAffrows();
+            foreach (var dt in new[] { DateTime.Parse("2020-5-6 0:1:2"), DateTime.Parse("2020-11-16 13:21:22"), })
+            {
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm:ss.ffffff"), select.First(a => dt.ToString()));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm:ss"), select.First(a => dt.ToString("yyyy-MM-dd HH:mm:ss")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm"), select.First(a => dt.ToString("yyyy-MM-dd HH:mm")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH"), select.First(a => dt.ToString("yyyy-MM-dd HH")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd"), select.First(a => dt.ToString("yyyy-MM-dd")));
+                Assert.Equal(dt.ToString("yyyy-MM"), select.First(a => dt.ToString("yyyy-MM")));
+                Assert.Equal(dt.ToString("yyyyMMdd"), select.First(a => dt.ToString("yyyyMMdd")));
+                Assert.Equal(dt.ToString("yyyyMM"), select.First(a => dt.ToString("yyyyMM")));
+                Assert.Equal(dt.ToString("yyyy"), select.First(a => dt.ToString("yyyy")));
+                Assert.Equal(dt.ToString("HH:mm:ss"), select.First(a => dt.ToString("HH:mm:ss")));
+                Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h")));
+                Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t").Replace("ÉÏÎç", "AM").Replace("ÏÂÎç", "PM").Replace("ÉÏ", "A").Replace("ÏÂ", "P"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t")));
+            }
+        }
         [Fact]
         public void Now()
         {
@@ -575,26 +612,6 @@ namespace FreeSql.Tests.Odbc.MySqlExpression
             //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
             //WHERE ((date_add(a__Type__Parent.`Time2`, interval (1) year) = now()))
         }
-        [Fact]
-        public void this_ToString()
-        {
-            var data = new List<object>();
-            data.Add(select.Where(a => a.CreateTime.ToString().Equals(DateTime.Now)).ToList());
-            data.Add(select.Where(a => a.Type.Time.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
-            data.Add(select.Where(a => a.Type.Parent.Time2.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a.`Title` as4, a.`CreateTime` as5 
-            //FROM `tb_topic111333` a 
-            //WHERE ((date_format(a.`CreateTime`, '%Y-%m-%d %H:%i:%s.%f') = now()));
-
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
-            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type 
-            //WHERE ((date_format(date_add(a__Type.`Time`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()));
-
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
-            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
-            //WHERE ((date_format(date_add(a__Type__Parent.`Time2`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()))
-        }
-
         [Fact]
         public void DateTime_Compare()
         {

FreeSql.Tests/FreeSql.Tests.Provider.Odbc/SqlServer/SqlServerExpression/DateTimeTest.cs

@@ -63,6 +63,7 @@ namespace FreeSql.Tests.Odbc.SqlServerExpression
                 Assert.Equal(dt.ToString("yyyyMM"), select.First(a => dt.ToString("yyyyMM")));
                 Assert.Equal(dt.ToString("yyyy"), select.First(a => dt.ToString("yyyy")));
                 Assert.Equal(dt.ToString("HH:mm:ss"), select.First(a => dt.ToString("HH:mm:ss")));
+                Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h")));
                 Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t").Replace("ÉÏÎç", "AM").Replace("ÏÂÎç", "PM").Replace("ÉÏ", "A").Replace("ÏÂ", "P"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t")));
             }
         }

FreeSql.Tests/FreeSql.Tests/MySql/MySqlExpression/DateTimeTest.cs

@@ -41,6 +41,43 @@ namespace FreeSql.Tests.MySqlExpression
             public List<TestTypeInfo> Types { get; set; }
             public DateTime Time2 { get; set; }
         }
+
+        [Fact]
+        public void this_ToString()
+        {
+            var data = new List<object>();
+            data.Add(select.Where(a => a.CreateTime.ToString().Equals(DateTime.Now)).ToList());
+            data.Add(select.Where(a => a.Type.Time.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
+            data.Add(select.Where(a => a.Type.Parent.Time2.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a.`Title` as4, a.`CreateTime` as5 
+            //FROM `tb_topic111333` a 
+            //WHERE ((date_format(a.`CreateTime`, '%Y-%m-%d %H:%i:%s.%f') = now()));
+
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
+            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type 
+            //WHERE ((date_format(date_add(a__Type.`Time`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()));
+
+            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
+            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
+            //WHERE ((date_format(date_add(a__Type__Parent.`Time2`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()))
+
+            g.mysql.Insert(new Topic()).ExecuteAffrows();
+            foreach (var dt in new[] { DateTime.Parse("2020-5-6 0:1:2"), DateTime.Parse("2020-11-16 13:21:22"), })
+            {
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm:ss.ffffff"), select.First(a => dt.ToString()));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm:ss"), select.First(a => dt.ToString("yyyy-MM-dd HH:mm:ss")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH:mm"), select.First(a => dt.ToString("yyyy-MM-dd HH:mm")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd HH"), select.First(a => dt.ToString("yyyy-MM-dd HH")));
+                Assert.Equal(dt.ToString("yyyy-MM-dd"), select.First(a => dt.ToString("yyyy-MM-dd")));
+                Assert.Equal(dt.ToString("yyyy-MM"), select.First(a => dt.ToString("yyyy-MM")));
+                Assert.Equal(dt.ToString("yyyyMMdd"), select.First(a => dt.ToString("yyyyMMdd")));
+                Assert.Equal(dt.ToString("yyyyMM"), select.First(a => dt.ToString("yyyyMM")));
+                Assert.Equal(dt.ToString("yyyy"), select.First(a => dt.ToString("yyyy")));
+                Assert.Equal(dt.ToString("HH:mm:ss"), select.First(a => dt.ToString("HH:mm:ss")));
+                Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h")));
+                Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t").Replace("ÉÏÎç", "AM").Replace("ÏÂÎç", "PM").Replace("ÉÏ", "A").Replace("ÏÂ", "P"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t")));
+            }
+        }
         [Fact]
         public void Now()
         {
@@ -575,25 +612,6 @@ namespace FreeSql.Tests.MySqlExpression
             //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
             //WHERE ((date_add(a__Type__Parent.`Time2`, interval (1) year) = now()))
         }
-        [Fact]
-        public void this_ToString()
-        {
-            var data = new List<object>();
-            data.Add(select.Where(a => a.CreateTime.ToString().Equals(DateTime.Now)).ToList());
-            data.Add(select.Where(a => a.Type.Time.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
-            data.Add(select.Where(a => a.Type.Parent.Time2.AddYears(1).ToString().Equals(DateTime.Now)).ToList());
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a.`Title` as4, a.`CreateTime` as5 
-            //FROM `tb_topic111333` a 
-            //WHERE ((date_format(a.`CreateTime`, '%Y-%m-%d %H:%i:%s.%f') = now()));
-
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
-            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type 
-            //WHERE ((date_format(date_add(a__Type.`Time`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()));
-
-            //SELECT a.`Id` as1, a.`Clicks` as2, a.`TypeGuid` as3, a__Type.`Guid` as4, a__Type.`ParentId` as5, a__Type.`Name` as6, a__Type.`Time` as7, a.`Title` as8, a.`CreateTime` as9 
-            //FROM `tb_topic111333` a, `TestTypeInfo333` a__Type, `TestTypeParentInfo23123` a__Type__Parent 
-            //WHERE ((date_format(date_add(a__Type__Parent.`Time2`, interval (1) year), '%Y-%m-%d %H:%i:%s.%f') = now()))
-        }
 
         [Fact]
         public void DateTime_Compare()

FreeSql.Tests/FreeSql.Tests/SqlServer/SqlServerExpression/DateTimeTest.cs

@@ -71,6 +71,7 @@ namespace FreeSql.Tests.SqlServerExpression
                 Assert.Equal(dt.ToString("yyyyMM"), select.First(a => dt.ToString("yyyyMM")));
                 Assert.Equal(dt.ToString("yyyy"), select.First(a => dt.ToString("yyyy")));
                 Assert.Equal(dt.ToString("HH:mm:ss"), select.First(a => dt.ToString("HH:mm:ss")));
+                Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h")));
                 Assert.Equal(dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t").Replace("ÉÏÎç", "AM").Replace("ÏÂÎç", "PM").Replace("ÉÏ", "A").Replace("ÏÂ", "P"), select.First(a => dt.ToString("yyyy MM dd HH mm ss yy M d H hh h m s tt t")));
             }
         }

Providers/FreeSql.Provider.MySql/MySqlExpression.cs

@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Text;
+using System.Text.RegularExpressions;
 
 namespace FreeSql.MySql
 {
@@ -392,7 +393,54 @@ namespace FreeSql.MySql
                         break;
                     case "Equals": return $"({left} = {args1})";
                     case "CompareTo": return $"timestampdiff(microsecond,{args1},{left})";
-                    case "ToString": return exp.Arguments.Count == 0 ? $"date_format({left}, '%Y-%m-%d %H:%i:%s.%f')" : null;
+                    case "ToString":
+                        if (exp.Arguments.Count == 0) return $"date_format({left}, '%Y-%m-%d %H:%i:%s.%f')";
+                        switch (args1)
+                        {
+                            case "'yyyy-MM-dd HH:mm:ss'": return $"date_format({left}, '%Y-%m-%d %H:%i:%s')";
+                            case "'yyyy-MM-dd HH:mm'": return $"date_format({left}, '%Y-%m-%d %H:%i')";
+                            case "'yyyy-MM-dd HH'": return $"date_format({left}, '%Y-%m-%d %H')";
+                            case "'yyyy-MM-dd'": return $"date_format({left}, '%Y-%m-%d')";
+                            case "'yyyy-MM'": return $"date_format({left}, '%Y-%m')";
+                            case "'yyyyMMdd'": return $"date_format({left}, '%Y%m%d')";
+                            case "'yyyyMM'": return $"date_format({left}, '%Y%m')";
+                            case "'yyyy'": return $"date_format({left}, '%Y')";
+                            case "'HH:mm:ss'": return $"date_format({left}, '%H:%i:%s')";
+                        }
+                       
+                        args1 = Regex.Replace(args1, "(yyyy|yy|MM|M|dd|d|HH|H|hh|h|mm|ss|tt)", m =>
+                        {
+                            switch (m.Groups[1].Value)
+                            {
+                                case "yyyy": return $"%Y";
+                                case "yy": return $"%y";
+                                case "MM": return $"%_a1";
+                                case "M": return $"%c";
+                                case "dd": return $"%d";
+                                case "d": return $"%e";
+                                case "HH": return $"%H";
+                                case "H": return $"%k";
+                                case "hh": return $"%h";
+                                case "h": return $"%l";
+                                case "mm": return $"%i";
+                                case "ss": return $"%_a2";
+                                case "tt": return $"%p";
+                            }
+                            return m.Groups[0].Value;
+                        });
+                        var isMatched = false;
+                        args1 = Regex.Replace(args1, "(m|s|t)", m =>
+                        {
+                            isMatched = true;
+                            switch (m.Groups[1].Value)
+                            {
+                                case "m": return $"'), trim(leading '0' from date_format({left}, '%i')), date_format({left}, '";
+                                case "s": return $"'), trim(leading '0' from date_format({left}, '%s')), date_format({left}, '";
+                                case "t": return $"'), trim(trailing 'M' from date_format({left}, '%p')), date_format({left}, '";
+                            }
+                            return m.Groups[0].Value;
+                        }).Replace("%_a1", "%m").Replace("%_a2", "%s");
+                        return isMatched == false ? $"date_format({left}, {args1})" : $"concat(date_format({left}, {args1}))".Replace($"date_format({left}, '')", "''");
                 }
             }
             return null;

Providers/FreeSql.Provider.Odbc/MySql/OdbcMySqlExpression.cs

@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Text;
+using System.Text.RegularExpressions;
 
 namespace FreeSql.Odbc.MySql
 {
@@ -392,7 +393,54 @@ namespace FreeSql.Odbc.MySql
                         break;
                     case "Equals": return $"({left} = {args1})";
                     case "CompareTo": return $"timestampdiff(microsecond,{args1},{left})";
-                    case "ToString": return exp.Arguments.Count == 0 ? $"date_format({left}, '%Y-%m-%d %H:%i:%s.%f')" : null;
+                    case "ToString":
+                        if (exp.Arguments.Count == 0) return $"date_format({left}, '%Y-%m-%d %H:%i:%s.%f')";
+                        switch (args1)
+                        {
+                            case "'yyyy-MM-dd HH:mm:ss'": return $"date_format({left}, '%Y-%m-%d %H:%i:%s')";
+                            case "'yyyy-MM-dd HH:mm'": return $"date_format({left}, '%Y-%m-%d %H:%i')";
+                            case "'yyyy-MM-dd HH'": return $"date_format({left}, '%Y-%m-%d %H')";
+                            case "'yyyy-MM-dd'": return $"date_format({left}, '%Y-%m-%d')";
+                            case "'yyyy-MM'": return $"date_format({left}, '%Y-%m')";
+                            case "'yyyyMMdd'": return $"date_format({left}, '%Y%m%d')";
+                            case "'yyyyMM'": return $"date_format({left}, '%Y%m')";
+                            case "'yyyy'": return $"date_format({left}, '%Y')";
+                            case "'HH:mm:ss'": return $"date_format({left}, '%H:%i:%s')";
+                        }
+
+                        args1 = Regex.Replace(args1, "(yyyy|yy|MM|M|dd|d|HH|H|hh|h|mm|ss|tt)", m =>
+                        {
+                            switch (m.Groups[1].Value)
+                            {
+                                case "yyyy": return $"%Y";
+                                case "yy": return $"%y";
+                                case "MM": return $"%_a1";
+                                case "M": return $"%c";
+                                case "dd": return $"%d";
+                                case "d": return $"%e";
+                                case "HH": return $"%H";
+                                case "H": return $"%k";
+                                case "hh": return $"%h";
+                                case "h": return $"%l";
+                                case "mm": return $"%i";
+                                case "ss": return $"%_a2";
+                                case "tt": return $"%p";
+                            }
+                            return m.Groups[0].Value;
+                        });
+                        var isMatched = false;
+                        args1 = Regex.Replace(args1, "(m|s|t)", m =>
+                        {
+                            isMatched = true;
+                            switch (m.Groups[1].Value)
+                            {
+                                case "m": return $"'), trim(leading '0' from date_format({left}, '%i')), date_format({left}, '";
+                                case "s": return $"'), trim(leading '0' from date_format({left}, '%s')), date_format({left}, '";
+                                case "t": return $"'), trim(trailing 'M' from date_format({left}, '%p')), date_format({left}, '";
+                            }
+                            return m.Groups[0].Value;
+                        }).Replace("%_a1", "%m").Replace("%_a2", "%s");
+                        return isMatched == false ? $"date_format({left}, {args1})" : $"concat(date_format({left}, {args1}))".Replace($"date_format({left}, '')", "''");
                 }
             }
             return null;