Sql trigger's query - mysql

Question

I am trying to create custom id for my table in the following format
2 random alphabets - 00MaxID
for e.g: AA-001
I have tried writing a query for it but it is not working, this is my first time writing a trigger also writing a complex query such as this.
UPDATED-2
the following query gives me an error near "SELECT count(cus_id) INTO #ct FROM customer;"
CREATE
TRIGGER `id_gen` BEFORE INSERT
ON `testdb`.`customer`
FOR EACH ROW BEGIN
SELECT count(cus_id) INTO #ct FROM customer;
IF #ct < 1000 THEN
SET #cs_id = LPAD(#ct+1, 3, 0 );
ELSE
SET #cs_id = #ct+1;
END IF;
SET NEW.cus_id = CONCAT(CHAR(FLOOR(65 + RAND() * 26),FLOOR(65 + RAND() * 26)),'-',#cs_id);
END;
Error
SQL query: Documentation
CREATE
TRIGGER `id_gen` BEFORE INSERT
ON `testdb`.`customer`
FOR EACH ROW BEGIN
SELECT count(cus_id) INTO #ct FROM customer
MySQL said: Documentation
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 6
Executing with Trigger Section

Answer 1

Answered by #Solarflare.
In the screenshot, you can see that phpmyadmin automatically added code including for each row, which is now twice in the statement (thus the error). Your own code will start with begin.
BEGIN
SELECT count(cus_id)+1 INTO #ct FROM customer;
IF #ct < 1000 THEN
SET #cs_id = LPAD(#ct, 3, 0 );
ELSE
SET #cs_id = #ct;
END IF;
SET NEW.cus_id = CONCAT(CHAR(FLOOR(65 + RAND() * 26),FLOOR(65 + RAND() * 26)),'-',#cs_id);
END;