MySQL如何循環存儲過程？

Question

我有一個名爲的存儲過程Evaluate（something1，something2）; 評估將採取一些參數，在數據庫中搜索它們並將結果插入結果表中。

現在我想創建一些類型的存儲過程，它將不斷調用Evaluate遍歷整個逗號分隔文件。這可能嗎？

僞代碼

assessEntireFile() 
{ 
    loop file 
    Evaluate(single line from file) 
    end loop 
} 



**The work flow of assessEntireFile() will be as followed:** 
1. call assessEntireFile() 
    --assessEntireFile will load and iterate over an input file (line-by-line) 
2. each iteration will call Evaluate() on that line 
    --evualte() will produce results in a table 
3. complete 

Answer 1

DELIMITER $$ 

CREATE PROCEDURE assessEntireTable() 
    READS SQL DATA 
BEGIN 

-- Declare variables according to your table/file structure 
    DECLARE field1 int DEFAULT 0; 
    DECLARE field2 VARCHAR(250) CHARACTER SET utf8; 
-- /Declare variables according to your table/file structure 

    DECLARE done int DEFAULT 0; 
    DECLARE currentrow CURSOR FOR SELECT * FROM assessEntireFileTmp; 
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1; 

    OPEN currentrow; 
-- Adapt next line according to your table/file structure 
    FETCH currentrow INTO field1,field2, ... ; 
    WHILE done=0 DO 
-- Adapt next 2 lines according to your table/file structure 
    CALL Evaluate(field1, field2, ...); 
    FETCH currentrow INTO field1,field2, ... ; 
    END WHILE; 
END $$ 

CREATE PROCEDURE assessEntireFile() 
BEGIN 
    DROP TABLE IF EXISTS assessEntireFileTmp; 
    CREATE TABLE assessEntireFileTmp (

-- Your needed structure here 

); 
    LOAD DATA INFILE '<file_name>' 
    INTO TABLE assessEntireFileTmp 
-- More needed parameters here 
    ; 

    CALL assessEntireTable(); 

    DROP TABLE assessEntireFileTmp; 
END $$ 

DELIMITER ; 

Answer 2

您可以在SQL

@count = 1 
while @count < 1000 
    begin 
    update etc 
@count = @count + 1 
end 

http://msdn.microsoft.com/en-us/library/ms178642.aspx