From fd372a69bd71a4142ecc2733646614bb53a08a7e Mon Sep 17 00:00:00 2001 From: AlexLEWIS Date: Mon, 27 Sep 2021 13:28:40 +0800 Subject: [PATCH] Created With Sql (markdown) --- With-Sql.md | 269 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 269 insertions(+) create mode 100644 With-Sql.md diff --git a/With-Sql.md b/With-Sql.md new file mode 100644 index 0000000..7fa6121 --- /dev/null +++ b/With-Sql.md @@ -0,0 +1,269 @@ +[中文](withsql) | **English** + +# WithSql 自定义SQL + +定义实体类 +```csharp + public class TestClass + { + [Column(Name = "ID", IsPrimary = true)] + public string No { get; set; } + public int? Age { get; set; } + public string Name { get; set; } + [Column(Name = "BIRTH_DAY")] + public DateTime? Birthday { get; set; } + public decimal Point { get; set; } + public Sex? Sex { get; set; } + } + public class TestClssDto + { + public string ID { get; set; } + + public int? Age { get; set; } + } +``` + +不同的查询方式。 +- 返回`DataTable` +- 返回`List` 即`List<(string,string)>`元组 +- 返回`List` 且能支持分页 +- 返回`List`且能支持分页 + +### 1.返回DataTable + +```csharp +DataTable dt1 = _fsql.Select() + .WithSql("select * from TestClass ") + .ToDataTable("ID,Age"); +``` + +```sql +SELECT ID,Age + FROM(select * from TestClass ) a +``` + +### 2.返回DataTable + +```csharp +DataTable dt2 = _fsql.Select() + .WithSql("select * from TestClass ") + .ToDataTable("*"); +``` +```sql +SELECT * +FROM ( select * from TestClass ) a +``` + +### 3.返回`List` 即`List<(string,string)>` 元组 + +```csharp +List<(string,string)> list1 = _fsql + .Select() + .WithSql("select * from TestClass ") + .ToList<(string, string)>("ID,Age"); +``` + +```sql +SELECT ID, Age + FROM(select * from TestClass ) a +``` + +### 4.返回`List` + +```csharp +var list2 = _fsql.Select() + .WithSql("select * from TestClass ") + .ToList("*"); +``` +```sql +SELECT * + FROM(select * from TestClass ) a +``` + +### 5.返回`List` 且能支持分页 + +```csharp + var list3 = _fsql.Select() + .WithSql("select * from TestClass ") + .WhereIf(true, "1=1") + .Page(1, 10).OrderBy("ID DESC") + .ToList("ID,Age"); +``` +```sql +SELECT ID, Age + FROM(select * from TestClass ) a + WHERE(1 = 1) + ORDER BY ID DESC + limit 0,10 +``` + +### 6.返回`List`且能支持分页 + +```csharp +var list4 = _fsql.Select() + .WithSql("select * from TestClass ") + .WhereIf(true, "1=1") + .Page(1, 10) + .OrderBy("ID DESC") + .ToList("ID,Age"); +``` + +```sql +SELECT ID, Age + FROM(select * from TestClass ) a + WHERE(1 = 1) + ORDER BY ID DESC + limit 0,10 +``` + + +## 通过 WithSql+ ToSQL实现 Union ALL 查询方法 + +### 1、二次 ISelect 查询：WithSql 使用多次，等于 UNION ALL 查询 + +WithSql 使用多次为 UNION ALL 查询，所以我们可以利用 ISelect.ToSql(FieldAliasOptions.AsProperty) 得到生成的 SQL，如下： + +```csharp +var sql1 = fsql.Select() + .Where(a => a.Title.Contains("xxx")) + .ToSql(); +var sql2 = fsql.Select() + .Where(a => a.Title.Contains("yyy")) + .ToSql(); + +fsql.Select() + .WithSql(sql1) + .WithSql(sql2) + .ToList(); +``` + +```sql +SELECT * from (SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` +FROM ( SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` + FROM `tb_topic` a + WHERE ((a.`Title`) LIKE '%xxx%') ) a) ftb + +UNION ALL + +SELECT * from (SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` +FROM ( SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` + FROM `tb_topic` a + WHERE ((a.`Title`) LIKE '%yyy%') ) a) ftb +``` + +### 2、跨分表查询：AsTable 相同实体多次操作，等于 Union ALL 查询 + +```c# +var sql = fsql.Select() + .AsTable((type, oldname) => "table_1")a + .AsTable((type, oldname) => "table_2") + .ToSql(a => a.Id); +``` + +```sql +select * from (SELECT a."Id" as1 FROM "table_1" a) ftb +UNION ALL +select * from (SELECT a."Id" as1 FROM "table_2" a) ftb +``` + +### 3、利用 ToSql 拼接新的 SQL，使用 IAdo 执行 + +```c# +var sql1 = fsql.Select() + .Where(a => a.Id > 100 && a.Id < 200) + .ToSql(a => new { a.Id, a.Title }, FieldAliasOptions.AsProperty); +var sql2 = fsql.Select() + .Where(a => a.Id > 1001 && a.Id < 1200) + .ToSql(a => new { a.Id, a.Title }, FieldAliasOptions.AsProperty); + +fsql.Ado.CommandFluent($"{sql1} UNION ALL {sql2}") + .ExecuteDataTable(); +``` + + + +## 分页问题 +Union All 之后 如果直接 分页会有一个问题。请看具体示例 + + +### 多次WithSql+Page存在问题：每个WithSql内都有一个Page分页 +```csharp +var sql1 = fsql.Select() + .Where(a => a.Title.Contains("xxx")) + .ToSql(); +var sql2 = fsql.Select() + .Where(a => a.Title.Contains("yyy")) + .ToSql(); + +fsql.Select().WithSql(sql1).WithSql(sql2).Page(1, 20).ToList(); +``` + +```sql + SELECT * from (SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` +FROM ( SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` + FROM `tb_topic` a + WHERE ((a.`Title`) LIKE '%xxx%') ) a +limit 0,20) ftb + +UNION ALL + +SELECT * from (SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` +FROM ( SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` + FROM `tb_topic` a + WHERE ((a.`Title`) LIKE '%yyy%') ) a +limit 0,20) ftb + +``` + +多个sql union all使用withsql，直接Page分页，会导致每个子表都生效，子表都生成分页。 + +WithSql 可以和 AsTable 实现分表的功能。 + +分表跨表查询的时候，分页是要向每个子表（即每个WithSql中的SQL分页）都生效。 + +## Solution + +### Call WithSql Multiple Times + +Call WithSql multiple times. If you need to paging, you need to follow the two steps below. + +- Step 1: combine the two Sql statements into one by `WithSql`: + +```csharp + var sql = fsql.Select() + .WithSql("SELECT * FROM tb_topic where id > 11") + .WithSql("SELECT * FROM tb_topic where id < 10") + .ToSql("*") +``` + +The above code will be generated as a Sql statement using `UNION ALL`: + +```sql + SELECT * from (SELECT * + FROM ( SELECT * FROM tb_topic where id > 11 ) a) ftb + + UNION ALL + + SELECT * from (SELECT * + FROM ( SELECT * FROM tb_topic where id < 10 ) a) ftb +``` + +- Step 2: on the basis of the SQL statement containing `UNION ALL`, page by calling the `Page` method: + +```csharp + var sql2 = g.mysql.Select() + .WithSql(sql) + .Page(2, 10) + .ToSql(); +``` +```sql +SELECT a.`Id`, a.`Clicks`, a.`TypeGuid`, a.`Title`, a.`CreateTime` +FROM ( SELECT * from (SELECT * + FROM ( SELECT * FROM tb_topic where id > 11 ) a) ftb + + UNION ALL + + SELECT * from (SELECT * + FROM ( SELECT * FROM tb_topic where id < 10 ) a) ftb ) a +limit 10,10 +``` \ No newline at end of file