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How to replace all letters with '*' apart from first ones in a column which has names and surnames in it in SQL Server

Bauer

In this column I was able to only query of the first letters (thanks to a guy from Stackoverflow).

For example:

John Snow after query becomes J S Lora White after query becomes L W

But I need to replace all remaining letter with *

John Snow should become J*** S*** Jonathan Conan J******* C****

This is the code:

SELECT 
    Personal info, SUBSTRING([Primary Contact], 1, 1) + ' ' +
                   SUBSTRING([Primary Contact], CHARINDEX(' ', [Primary Contact]) + 1, 1) AS CI 
FROM 
    xx