how to concatenate string in sql code example

Example 1: sql server concat string and int

SELECT 'Comments: ' + CAST(9 AS varchar(12)) AS Result;

Example 2: concatenation in sql

We use "||" to concatenation in Sql

example:
WHERE LOWER(FIRST_NAME || LAST_NAME)  LIKE '%d%' ;

Example 3: concat two columns in sql server

select Convert(nvarchar(50),ID)+'-'+Convert(nvarchar(50),Year) as ID_Year from tablename