Check out example codes for "concat in mysql". It will help you in understanding the concepts better.

Code Example 1

CONCAT (string1, string2,…) AS column_name

Code Example 2

SELECT CONCAT ('C', 'at') "concat" FROM DUMMY;

Code Example 3

CONCAT (string1, string2,…)

Code Example 4

SELECT 
    column1,column2,...
FROM
    table_name
WHERE 
	(expr|column_1) IN ('value1','value2',...);

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