IBM DB2 Control Loop

Question

我正在从MS SQL Server迁移到IBM DB2（版本9.7）。尝试使用局部变量（不是存储过程的一部分）编写复合SQL While循环，类似于 -

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

我认为您的问题与语句终止符有关（如果您提供实际错误，则更容易看到）。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.

在这里，我使用@作为语句终止符;有特殊意义。如果你不想改变语句终止符，那就是“隐藏”;在复合语句中，通过在行尾添加注释：

[ ... ]$ 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.