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POCommon table expression from bottom-top approach
 

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  1. POCommon table expression from bottom-top approach
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    <p>I have an Agent table and a hierarchy table.</p> <pre><code>CREATE TABLE [dbo].[Agent]( [AgentID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [varchar](50) NULL, [LastName] [varchar](50) NULL, CONSTRAINT [PK_Agent] PRIMARY KEY CLUSTERED ( [AgentID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO CREATE TABLE [dbo].[Hierarchy]( [HierarchyID] [int] IDENTITY(1,1) NOT NULL, [AgentID] [int] NULL, [NextAgentID] [int] NULL, CONSTRAINT [PK_Hierarchy] PRIMARY KEY CLUSTERED ( [HierarchyID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO </code></pre> <p>--Insert to Agent</p> <pre><code>INSERT INTO [Agent]([FirstName],[LastName])VALUES('C1','C1'); INSERT INTO [Agent]([FirstName],[LastName])VALUES('C2','C2'); INSERT INTO [Agent]([FirstName],[LastName])VALUES('C3','C3'); INSERT INTO [Agent]([FirstName],[LastName])VALUES('C4','C4'); SELECT * FROM Agent; AgentID FirstName LastName 1 C1 C1 2 C2 C2 3 C3 C3 4 C4 C4 </code></pre> <p>--Insert to Hierarchy</p> <pre><code>INSERT INTO [Hierarchy] ([AgentID],[NextAgentID]) VALUES (1,NULL); INSERT INTO [Hierarchy] ([AgentID],[NextAgentID]) VALUES (2,1); INSERT INTO [Hierarchy] ([AgentID],[NextAgentID]) VALUES (3,2); INSERT INTO [Hierarchy] ([AgentID],[NextAgentID]) VALUES (2,4); INSERT INTO [Hierarchy] ([AgentID],[NextAgentID]) VALUES (4,NULL); SELECT * FROM Hierarchy; HierarchyID AgentID NextAgentID 1 1 NULL 2 2 1 3 3 2 4 2 4 5 4 NULL </code></pre> <p>I used a common table expression to determine the bottom to top levels</p> <pre><code>WITH AgentHierarchy(AgentID, NextAgentID, HierarchyLevel) AS ( SELECT H1.AgentID, H1.NextAgentID, 1 HierarchyLevel FROM Hierarchy H1 WHERE NOT EXISTS (SELECT 1 FROM Hierarchy H2 WHERE H2.NextAgentID = H1.AgentID) UNION ALL SELECT H.AgentID, H.NextAgentID, (AgentHierarchy.HierarchyLevel + 1) HierarchyLevel FROM Hierarchy H INNER JOIN AgentHierarchy ON AgentHierarchy.NextAgentID = H.AgentID ) SELECT DISTINCT AgentID, NextAgentID, HierarchyLevel FROM AgentHierarchy ORDER BY AgentID, NextAgentID, HierarchyLevel; </code></pre> <p>Result is:</p> <pre><code>AgentID NextAgentID HierarchyLevel 1 NULL 3 2 1 2 3 2 1 4 NULL 1 2 4 1 </code></pre> <p>My requirement is to show this in the below way:</p> <pre><code>AgentID NextAgentID HierarchyLevel 1 NULL 1 2 1 1 3 2 1 3 1 2 4 NULL 1 2 4 1 3 4 2 </code></pre> <p>In short, recursively all the hierarchy with levels should be pulled with bottom-to-top approach. Please help me...</p>
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    1. This table or related slice is empty.
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
 

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