Asignar valor a variable dentro de if

[jnavarrete2311]

Ya logre crearlo ya solo tenia errores de sintaxis en campos que tenian espacio asi quedo la solucion en workbench:
-- --------------------------------------------------------------------------------
-- Routine DDL
-- Note: comments before and after the routine body will not be stored by the server
-- --------------------------------------------------------------------------------
DELIMITER $$

Código MySQL:

-- --------------------------------------------------------------------------------
-- Routine DDL
-- Note: comments before and after the routine body will not be stored by the server
-- --------------------------------------------------------------------------------
DELIMITER $$
 
CREATE PROCEDURE `sp_InsertCustomer` (
    IN Firstname VARCHAR(100), 
    IN Lastname VARCHAR(100), 
    IN Email VARCHAR(100), 
    IN Birthday DATETIME,
    
    IN Company VARCHAR(100), 
    IN Address1 VARCHAR(100), 
    IN Postcode INT, 
    IN City VARCHAR(100), 
    IN Phone INT
)
BEGIN
 
    DECLARE regs INT;
    DECLARE ExistsUser   INT;
    DECLARE Customer_ID INT;
    SET regs = 0;
    SELECT COUNT(*) INTO regs
    FROM `ps_customer` 
    WHERE id_customer = 3;
 
    IF regs > 0 THEN
        SET ExistsUser = 1;
    END IF;
 
    IF ExistsUser = 1 THEN
        INSERT INTO  `ps_customer`
            (id_default_group,id_risk,firstname,lastname,email, passwd,birthday, newsletter_date_add,max_payment_days,secure_key,active,date_add,date_upd)
        VALUES(
               3, 0, Firstname, Lastname, Email, '12345',Birthday,'0000-00-00 00:00:00',0,
               '2293b4751c4ff4517bb997eb9c141a76',1,CURRENT_TIMESTAMP(),CURRENT_TIMESTAMP()
              );
 
        SET Customer_ID = LAST_INSERT_ID();
        IF Customer_ID > 0 THEN
            INSERT INTO  `ps_customer_group` (id_customer, id_group)
                VALUES(Customer_ID, 3);
            INSERT INTO  `ps_guest`(id_operating_system, id_web_browser, id_customer, screen_resolution_x, screen_resolution_y,
            screen_color, sun_java, adobe_flash, adobe_director, apple_quicktime, real_player, windows_media, accept_language)
                VALUES(3, 10, Customer_ID, 0, 0, 0, 0, 0, 0, 0, 0, 0,'');
            INSERT INTO  `ps_address`(id_country, id_state, id_customer, id_manufacturer, id_supplier, id_warehouse, alias, company, lastname, firstname, address1,
             postcode, city, phone, vat_number, dni, DATE_ADD, date_upd, active, deleted)
                VALUES(145, 67, Customer_ID, 0, 0, 0, 'Business', Company, Lastname, Firstname, Address1, Postcode, City, Phone, '','' , CURRENT_TIMESTAMP(), CURRENT_TIMESTAMP(), 1, 0);
        END IF;
    END IF;
 
END
 

AUNQUE LA VERDAD ME HA DEJADO UN MAL SABOR MYSQL YO NO RECOMIENDO QUE LO USEN ESTA MUY LIMITADO EN MUCHAS COSAS ES MUCHO MEJOR SQLSERVER Y NI HABLAR CON PHP QUE CONTINUA SIENDO TAN OBSOLETO Y NO PROPORCIONA MUCHA AYUDA PARA DESARROLLAR A LOS PROGRAMADORES, ESTAS DOS TECNOLOGIAS DE VERIAN DE MORIR YA.
GRACIAS POR LA AYUDA gnzsoloyo