Using “IN” in a WHERE clause where the number of items in the set is very large

Question

I have a situation where I need to do an update on a very large set of rows that I can only identify by their ID (since the target records are selected by the user and have noth

Answer 1

There are multiple ways of accommodating a large set of values in a where condition

1. Using Temp Tables

   Insert the values into a temp table with a single column.

   Create a UNIQUE INDEX on that particular column.

   INNER JOIN the required table with the newly created temp table

2. Using array-like functionality in SQL Server

   SQL does support an array like functionality

   check this link for full documentation.

SAMPLE SYNTAX :

Create TABLE #IDs (id int NOT NULL)
DECLARE @x varchar(max) = '' 
DECLARE @xParam XML;
SELECT @xParam = CAST('' + REPLACE(@x, ',', '') + '' AS XML)
INSERT into #IDs
SELECT x.i.value('.','NVARCHAR(100)') as key FROM @xParam .nodes('//i') x(i)
CREATE UNIQUE INDEX IX_#IDs ON #IDs (ID ASC) 

Query using

SELECT A.Name, A.Age from Table A 

INNER JOIN #IDs id on id.id = A.Key