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From: Erland Sommarskog <esquel@sommarskog.se>
Newsgroups: comp.databases.ms-sqlserver
Subject: Re: No covering indices for table types?
Date: Fri, 12 Jul 2024 23:48:29 +0200
Organization: Erland Sommarskog
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Anton Shepelev (anton.txt@g{oogle}mail.com) writes:
> Hello, all.
> 
> I wanted to create a convenient table-type for storing time
> series (with possibly non-uniqe sample marks):
> 
>   CREATE TYPE series_t AS TABLE
>   (  moment DATETIME NOT NULL,
>      value  FLOAT
>   )
> 
> For efficient querying and joining, I need a covering index
> on the [moment] field that includes [value], but the INCLUDE
> keyword does not seem to be suported:
> 

Starting with SQL 2019, it is:

CREATE TYPE series_t AS TABLE
  (  moment DATETIME NOT NULL,
     value  FLOAT,
     INDEX Main(moment) 
     INCLUDE (value)
  )

If you are an older version, I would suggest adding value as an index key
is the best in most situations.

I will submit an edit to the CREATE TYPE topic.