技術標籤：MySQLMySQL建立計算欄位

拼接欄位

SELECT CONCAT(vend_name, ' ( ', vend_country, ' ) ') FROM vendors ORDER BY vend_name;

SELECT TRIM(CONCAT(vend_name, ' ( ', vend_country, ' ) ')) AS vend_title FROM vendors ORDER BY vend_name;

SELECT RTRIM(CONCAT(vend_name, ' ( ', vend_country, ' ) ')) AS vend_title FROM
 
 vendors ORDER BY vend_name;

執行算術計算

SELECT * FROM orderitems WHERE order_num = 20008;

SELECT prod_id, quantity, item_price, quantity*item_price AS expanded_price FROM orderitems WHERE order_num = 20008;