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This function returns an estimated number of non-null unique values in a data set. It came with SQL Server 2019. Let’s create a table with the Identitiy column and add a few records to this table.
1 2 3 4 5 6 7 8 9 10 11 | CREATE TABLE [dbo].[MyTable1]( [ID] [int] IDENTITY(1,1) NOT NULL, [Name] [varchar](50) NULL ) ON [PRIMARY] GO INSERT INTO [dbo].[MyTable1] VALUES ('Nurullah CAKIR'), ('Faruk ERDEM'), ('Ogun OZALP'), ('Hakan GURBASLAR'), ('Dilara OZDEMIR') Select * FROM [dbo].[MyTable1] |
You can use the APPROX_COUNT_DISTINCT Function as follows.
1 | SELECT APPROX_COUNT_DISTINCT(ID) FROM [dbo].[MyTable1]; |
Since this function comes with SQL Server 2019, you will get the error as follows when you want to run this function in a previous version.
Msg 195, Level 15, State 10, Line 14
‘APPROX_COUNT_DISTINCT’ is not a recognized built-in function name.
You may also receive a “is not a recognized built-in function name” error if you did not specify the path of the function correctly.
