-- 過濾數據 SELECT prod_name,prod_price FROM Products WHERE prod_price = 3.49; -- WHERE子句操做符 SELECT prod_name,prod_price FROM Products WHERE prod_price < 10; SELECT prod_name,prod_price FROM Products WHERE prod_price > 10; SELECT prod_name,prod_price FROM Products WHERE prod_price <=10; -- 不匹配檢查 SELECT vend_id,prod_name FROM Products WHERE vend_id != 'DLL01'; -- 範圍值檢查 SELECT prod_name,prod_price FROM Products WHERE prod_price BETWEEN 5 AND 10; -- 空值檢查 SELECT cust_name FROM Customers WHERE cust_email IS NULL; -- 高級數據過濾 -- AND操做符 SELECT prod_id,prod_price,prod_name FROM Products WHERE vend_id = 'DLL01' AND prod_price <=4 ORDER BY prod_name; -- OR操做符 SELECT prod_name,prod_price FROM Products WHERE vend_id = 'DLL01' OR vend_id = 'BRS01'; -- 求值順序 SELECT prod_name,prod_price FROM Products WHERE (vend_id = 'DLL01' OR vend_id = 'BRS01' ) AND prod_price >= 10; -- IN操做符 SELECT prod_name,prod_price FROM Products WHERE vend_id IN ('DLL01','BRS01') ORDER BY prod_name; -- IN 操做符與 OR 操做符能夠實現相同的功能 SELECT prod_name,prod_price FROM Products WHERE vend_id = 'DLL01' OR vend_id = 'BRS01' ORDER BY prod_name; -- NOT 操做符 SELECT prod_name,vend_id FROM Products WHERE NOT vend_id = 'DLL01' ORDER BY prod_name; SELECT prod_name,vend_id FROM Products WHERE vend_id != 'DLL01' ORDER BY prod_name; -- 用通配符進行過濾 -- LIKE 操做符 -- % 通配符,能夠匹配0個,1個或者多個字符 SELECT prod_id,prod_name FROM Products WHERE prod_name LIKE 'Fish%'; -- 查找Fish開頭的名字 SELECT prod_id,prod_name FROM Products WHERE prod_name LIKE '%bean bag%'; -- 查找包含 bean bag 的名字,不管前面和後面是什麼 SELECT prod_name FROM Products WHERE prod_name LIKE 'F%y'; -- 查找以 F 開頭 y 結尾的名字 -- _ 通配符,只能匹配單個字符 SELECT prod_id,prod_name FROM Products WHERE prod_name LIKE '__ inch teddy bear'; SELECT prod_id,prod_name FROM Products WHERE prod_name LIKE '% inch teddy bear'; -- [] 通配符 mysql 不支持 SELECT cust_contact FROM Customers WHERE cust_contact LIKE '[JM]%' ORDER BY cust_contact; -- mysql 不支持 [] 通配符,能夠寫成如下這種形式 SELECT cust_contact FROM Customers WHERE cust_contact LIKE 'J%' OR cust_contact LIKE 'M%' ORDER BY cust_contact;