在存儲過程中

Question

我想在動態列名傳遞給計算其標準偏差動態SQL，在Oracle，下面是代碼：

CREATE OR REPLACE 
PROCEDURE ReportCalculate 
    (
    param_columnName IN VARCHAR2 DEFAULT 'COMPUTED_CP_MLIFTOFF_KNOT9OR10' 
) 
    AS 
    sqlstr VARCHAR2(500); 
    result NUMBER; 
    BEGIN 
    sqlstr:='select stddev(:col) from LIDISUDUXIAO where 1=1 and NO_10_LIMITSIGN_DEPART_ID<>0'; 
    execute immediate sqlstr into result using param_columnName; 
    DBMS_OUTPUT.PUT_LINE(result); 
    END; 

我採用默認參數調用它，錯誤消息是：

Procedure execution failed 
ORA-01722: invalid number 
ORA-06512: at "AGS.REPORTCALCULATE", line 10 
ORA-06512: at line 1 

我該如何解決它？

Answer 1

列名不能用作查詢的參數。你需要編輯sqlstr變量，包括所提供的param_columnName在查詢本身執行前：

CREATE OR REPLACE 
PROCEDURE ReportCalculate 
    (
    param_columnName IN VARCHAR2 DEFAULT 'COMPUTED_CP_MLIFTOFF_KNOT9OR10' 
) 
    AS 
    sqlstr VARCHAR2(500); 
    result NUMBER; 
    BEGIN 
    sqlstr:='select stddev(' || param_columnName || ') from LIDISUDUXIAO where 1=1 and NO_10_LIMITSIGN_DEPART_ID<>0'; 
    execute immediate sqlstr into result; 
    DBMS_OUTPUT.PUT_LINE(result); 
    END;