union 分页 /group/join 复杂查询 (.net core/framework)

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union 分页/group/join 复杂查询(.net core/framework)

unoin 是一个比较特殊的查询，对 union 进行分页，关联，分组需要在最外面包装一层，如果对 union 结果再进行其它关联，分组，复杂度直线上升，解决此问题

安装 nuget 包：CRL
using CRL;

以下为默认数据源实现

如果使用 ef core 和 ado.net 见:Data/EFTest · hubroxxl/CRL - 码云 - 开源中国 (gitee.com)

定义数据源

var builder = DBConfigRegister.GetInstance();builder.RegisterDBAccessBuild(dbLocation =>        {            return new DBAccessBuild(DBType.MSSQL, "server=.;database=testDb; uid=sa;pwd=123;");        });

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定义对象管理器

public class ProductRepository:BaseProvider<ProductData>{    public static ProductRepository Instance        {            get { return  new ProductRepository(); }        }}

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通过 GetLambdaQuery 方法创建 ILambdaQuery

ILambdaQuery 能实现子查询和嵌套查询，只要符合 T-SQL 语义逻辑，可以使用 ILambdaQueryResultSelect 无限叠加

如：

join 后 group
join 后再 join
group 后再 join
join 一个 group 结果
join 一个 union 结果
对 union 进行 group 再 join
...

简单的 union

var query = ProductRepository.Instance.GetLambdaQuery().Where(b => b.Id < 200);            var query2 = query.CreateQuery<Code.Order>().Where(b => b.Id < 200);            var view1 = query.Select(b => new { a1 = b.Id, a2 = b.ProductName });            var view2 = query2.Select(b => new { a1 = b.Id, a2 = b.Remark });            var result = view1.Union(view2).OrderBy(b => b.a1).OrderBy(b => b.a2, false).ToList();            var sql = query.PrintQuery();

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生成 SQL 为

select t1.[Id] as a1,t1.[ProductName1] as a2 from [ProductData] t1  with (nolock)  where (t1.[Id]<'200') union allselect t2.[Id] as a1,t2.[Remark] as a2 from [OrderProduct] t2  with (nolock)  where (t2.[Id]<'200')  order by [a1] desc,[a2] asc

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对 union 进行分页

var query = ProductRepository.Instance.GetLambdaQuery().Where(b => b.Id < 200);            query.Take(10);            var query2 = query.CreateQuery<Code.Order>().Where(b => b.Id < 200).Take(5);            var view1 = query.Select(b => new { a1 = b.Id, a2 = b.ProductName });            var view2 = query2.Select(b => new { a1 = b.Id, a2 = b.Remark });            var union = view1.Union(view2).OrderBy(b => b.a1).OrderBy(b => b.a2, false);            union.UnionPage(15, 1);//分页参数            var result = union.ToList();            var sql = query.PrintQuery();

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生成 SQL 为

SELECT * FROM (select a1,a2,ROW_NUMBER() OVER ( Order by [a1] desc,[a2] asc ) AS RowNumber  from (select top 10 t1.[Id] as a1,t1.[ProductName1] as a2 from [ProductData] t1  with (nolock)  where (t1.[Id]<200) union all select top 5 t2.[Id] as a1,t2.[Remark] as a2 from [OrderProduct] t2  with (nolock)  where (t2.[Id]<200)) tu) T WHERE T.RowNumber BETWEEN 1 AND 15 order by RowNumber

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union 后再 join

var query = ProductRepository.Instance.GetLambdaQuery().Where(b => b.Id < 200);            query.Take(10);            var query2 = query.CreateQuery<Code.Order>().Where(b => b.Id < 200).Take(5);            var view1 = query.Select(b => new { a1 = b.Id, a2 = b.ProductName });            var view2 = query2.Select(b => new { a1 = b.Id, a2 = b.Remark });            var union = view2.Union(view1).OrderBy(b => b.a1).OrderBy(b => b.a2, false);            var join = query.Join(union, (a, b) => a.Id == b.a1).Select((a, b) => new { a.Id, b.a2 });//join            var result = join.ToList();            var sql = query.PrintQuery();

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生成 SQL 为

select top 10 t1.[Id],t3.[a2] as a2 from [ProductData] t1  with (nolock)  Inner join (select top 5 t2.[Id] as a1,t2.[Remark] as a2 from [OrderProduct] t2  with (nolock)  where (t2.[Id]<'200') union all select top 10 t1.[Id] as a1,t1.[ProductName1] as a2 from [ProductData] t1  with (nolock)  where (t1.[Id]<'200')  order by [a1] desc,[a2] asc) t3  on t1.[Id]=t3.a1 where (t1.[Id]<'200')

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union 后再 group

var query = ProductRepository.Instance.GetLambdaQuery().Where(b => b.Id < 200);            var query2 = query.CreateQuery<Code.Order>().Where(b => b.Id < 200);            var view1 = query.Select(b => new { a1 = b.Id, a2 = b.ProductName });            var view2 = query2.Select(b => new { a1 = b.Id, a2 = b.Remark });            var union = view1.Union(view2).OrderBy(b => b.a2, false);            var group = union.UnionGroupBy(b => b.a2);//group            var result = group.Select(b => new { b.a2 }).ToList();            var sql = query.PrintQuery();

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生成 SQL 为

select a2 from (select t1.[Id] as a1,t1.[ProductName1] as a2 from [ProductData] t1  with (nolock)  where (t1.[Id]<'200') union allselect t2.[Id] as a1,t2.[Remark] as a2 from [OrderProduct] t2  with (nolock)  where (t2.[Id]<'200')) tu group by a2  order by [a2] asc

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源码示例参考

Data/QueryTest/test · hubroxxl/CRL - 码云 - 开源中国 (gitee.com)

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union 分页 /group/join 复杂查询 (.net core/framework)

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