IBM DB2 控制循环

Question

我正在从 MS SQL 服务器迁移到 IBM DB2（9.7 版）。尝试用局部变量（不是存储过程的一部分）编写复合 SQL While 循环，例如 -

BEGIN ATOMIC
   DECLARE i INT DEFAULT 12;
     WHILE i > 0 
     "DO ....";
     SET COUNT = COUNT - 1;
     END WHILE;
 END

但是我在第一行声明变量时遇到错误-

SQL0104N  An unexpected token "12" was found following "ECLARE I INT DEFAULT". Expected tokens may include:  "END-OF-STATEMENT"

非常感谢任何帮助。

Answer 1

我假设您的问题与语句终止符有关（如果您提供了您遇到的实际错误，则更容易查看）。我测试了以下内容并且有效：

[ ... ]$ cat aa.sql 

CREATE TABLE TEMP_ITERATIONS ( X VARCHAR(50) ) @

BEGIN ATOMIC 
    DECLARE i INT DEFAULT 12; 
    WHILE i > 0 DO 
        INSERT INTO TEMP_ITERATIONS VALUES ('IT'|| RTRIM(CHAR(i))); 
        SET i = i - 1; 
    END WHILE; 
END @

[ ... ]$ db2 -td@ -f aa.sql

DB20000I  The SQL command completed successfully.
DB20000I  The SQL command completed successfully.

[ ... ]$ db2 "select * from TEMP_ITERATIONS"

X                                                 
--------------------------------------------------
IT12                                              
IT11                                              
IT10
[...]
12 record(s) selected.

这里我使用@作为语句终止符，因为 ;有特殊的意义。如果您不想更改语句终止符，一个技巧是 "hide" the ;通过在行尾添加注释在复合语句中：

[ ... ]$ cat aa.sql 

CREATE TABLE TEMP_ITERATIONS ( X VARCHAR(50) ) ;

BEGIN ATOMIC 
    DECLARE i INT DEFAULT 12; --
    WHILE i > 0 DO 
        INSERT INTO TEMP_ITERATIONS VALUES ('IT'|| RTRIM(CHAR(i))); --
        SET i = i - 1; --
    END WHILE; --
END ;

[ ... ] db2 -tf aa.sql
DB20000I  The SQL command completed successfully.
DB20000I  The SQL command completed successfully.

[ ... ]$ db2 "select * from TEMP_ITERATIONS"

X                                                 
--------------------------------------------------
IT12                                              
IT11                                              
IT10
[...]
12 record(s) selected.

IBM DB2 控制循环

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