爲什麼這個MySQL函數返回NULL

Question

DELIMITER $$ 

USE `healthsystem`$$ 

DROP FUNCTION IF EXISTS `GetBillingProviderInfo`$$ 

CREATE DEFINER=`root`@`localhost` FUNCTION `GetBillingProviderInfo`(claimID LONG, claimInsCode VARCHAR(50)) RETURNS CHAR(50) DETERMINISTIC 
BEGIN 
    DECLARE varReturnValue      VARCHAR(5000); 
    DECLARE varProviderCode      VARCHAR(20); 
    DECLARE varLocationCode      VARCHAR(20); 
    DECLARE varFindCase      VARCHAR(10); 
    DECLARE varbillwithNPI        VARCHAR(2);  
    DECLARE varoverrideGroupNPI       BIT(1);   
    DECLARE varoverrideGroupNPIValue     VARCHAR(30); 
    DECLARE varbillwithSSN        VARCHAR(20); 
    DECLARE varoverrideTaxID       BIT(1);   
    DECLARE varoverrideTaxIDValue      VARCHAR(30); 
    DECLARE varoverrideName        BIT(1);   
    DECLARE varoverrideBillingNameValue     VARCHAR(50); 
    DECLARE varoverrideBillingAddress     BIT(1);   
    DECLARE varoverrideAddress1       VARCHAR(255); 
    DECLARE varoverrideAddress2       VARCHAR(255); 
    DECLARE varoverrideCity        VARCHAR(255); 
    DECLARE varoverrideState       VARCHAR(2);  
    DECLARE varoverrideZipCode       VARCHAR(20); 
    DECLARE varBoxNo33BillingName     VARCHAR(50); 
    DECLARE varBoxNo33Address1     VARCHAR(50); 
    DECLARE varBoxNo33Address2     VARCHAR(50); 
    DECLARE varBoxNo33City      VARCHAR(20); 
    DECLARE varBoxNo33State      VARCHAR(2); 
    DECLARE varBoxNo33ZipCode     VARCHAR(10); 
    DECLARE varLastName      VARCHAR(100); 
    DECLARE varFirstName      VARCHAR(100); 
    DECLARE varMiddleName      VARCHAR(100); 
    DECLARE varPracticeID      BIGINT; 
    DECLARE varrecordCount      INT; 
    RETURN varReturnValue; 



    RETURN CONCAT('Hello, ',s,'!'); 


    END$$ 

DELIMITER ; 

SELECT GetBillingProviderInfo(51,'MEDICARE-GHI'); 

Answer 1

因爲：

RETURN varReturnValue; 

你以後RETURN CONCAT('Hello, ',s,'!')沒有機會執行。