Question

我正在编写存储过程，其中汇总函数名称和列名称作为参数并返回值（例如：＆＃39; sum＆＃39; ，＆＃39; age＆＃39;）返回值（SELECT SUM（age）FROM myTable））

我的代码：

CREATE PROCEDURE sample (IN name VARCHAR(10), IN col VARCHAR(30), OUT result INT) 
BEGIN
    SELECT CONCAT( name , '(', col, ') ') INTO result FROM myTable;
END$

Answer 1

将其设为FUNCTION和

return CONCAT('SELECT ', name, '(', col, ') FROM myTable;');

Answer 2

使用Prepared Statements。

CREATE PROCEDURE sample (IN name VARCHAR(10), IN col VARCHAR(30), OUT result INT) 
BEGIN
    SET @sql := '';
    SET @ret := 0;

    SELECT CONCAT('SELECT ', name,  '(', col, ') INTO @ret FROM myTable') INTO @sql FROM DUAL;
    PREPARE STMT from @sql;
    EXECUTE STMT;

    SELECT @ret INTO result FROM DUAL;

    DEALLOCATE PREPARE STMT;     
END

MariaDB将聚合函数名称作为存储过程参数传递

2 个答案: