mysql：什麼是SELECT的ROW_COUNT（）信息函數？

Question

我在尋找內置返回剛纔選擇的行數，如ROW_COUNT（）確實爲INSERT，UPDATE，等

在一個存儲過程我希望做這個MySQL信息功能：

... 
select episode_name from bestLOSTepisodes 
set _episodes_found = SELECTED_ROWS(); 
... 

我已經做了大量的挖掘工作，並且一直無法找到像SELECTED_ROWS（）這樣的函數。

Answer 1

您可能想要使用FOUND_ROWS()函數。

例子：

CREATE TABLE users (id int, name varchar(20), age int); 

INSERT INTO users VALUES (1, 'Bob', 19); 
INSERT INTO users VALUES (2, 'Jack', 25); 
INSERT INTO users VALUES (3, 'Paul', 15); 
INSERT INTO users VALUES (4, 'Steve', 35); 
INSERT INTO users VALUES (5, 'Mark', 17); 

SELECT * FROM users WHERE age > 18; 
+------+-------+------+ 
| id | name | age | 
+------+-------+------+ 
| 1 | Bob | 19 | 
| 2 | Jack | 25 | 
| 4 | Steve | 35 | 
+------+-------+------+ 
3 rows in set (0.00 sec) 

SELECT FOUND_ROWS() as num_of_rows_found; 
+-------------------+ 
| num_of_rows_found | 
+-------------------+ 
|     3 | 
+-------------------+ 
1 row in set (0.00 sec) 

Answer 2

你必須在你的查詢SQL_CALC_FOUND_ROWS FOUND_ROWS：http://dev.mysql.com/doc/refman/5.0/en/information-functions.html#function_found-rows

Answer 3

您可以嘗試FOUND_ROWS（）函數。

CREATE TABLE Emp(EmpID int,EMPNAME varchar(20),SALARY int); 
INSERT INTO Emp VALUES (1,'Astin',6500); 
INSERT INTO Emp VALUES (2,'Blade',4500); 
INSERT INTO Emp VALUES (3,'Cabal',6500); 
INSERT INTO Emp VALUES (4,'Brant',5200); 
INSERT INTO Emp VALUES (5,'Sunny',7000); 
SELECT * FROM EMP WHERE SALARY=6500; 
SELECT FOUND_ROWS() as SelectedRowCount;