如何在DB2中组合两个游标

Question

我有两个游标如下：

EXEC SQL                                      
     DECLARE C1 CURSOR FOR               
     SELECT  DISTINCT FIELD_1                  
     FROM    TABLE                  
     WHERE   FIELD_2 BETWEEN :MAX_DATE
                        AND '9999-12-31'      
           AND   FIELD_3 =  :VALUE 
     WITH UR                                  
     FOR FETCH ONLY                           
END-EXEC

EXEC SQL                                      
     DECLARE C2 CURSOR FOR               
     SELECT  DISTINCT FIELD_1                  
     FROM    TABLE                  
     WHERE   FIELD_2 BETWEEN :MIN_DATE
                        AND '9999-12-31'      
           AND   FIELD_3 =  :VALUE 
     WITH UR                                  
     FOR FETCH ONLY                           
END-EXEC 

两个游标都指向同一个表。我如何组合两个游标？请让我知道一种方法来组合这两个表。

Answer 1

如果您只想组合两个游标的谓词，当然可以这样做。结合WHERE条款：

EXEC SQL                                      
     DECLARE C1 CURSOR FOR               
     SELECT  DISTINCT FIELD_1                  
     FROM    TABLE                  
     WHERE   FIELD_2 BETWEEN :MIN_DATE
                        AND :MAX_DATE
           AND   FIELD_3 =  :VALUE 
     WITH UR                                  
     FOR FETCH ONLY                           
END-EXEC

问题中的示例包含9999-12-31范围内的最小值和最大值，这对我没有意义。