在oracle存儲過程中動態地準備sql

Question

我有3個輸入參數，基於每個輸入參數的值，我必須動態地在過程中準備SQL。我正在做下面的方式，但它是失敗的，如果參數值爲空，那麼我必須從where子句中排除。

IN參數：

EMPID在VARCHAR2 || empname IN varchar2 || empsal IN VARCHAR2

SELECT 
     EMP_NAME 
INTO 
     V_EMP_NAME 
FROM 
     EMPLOYEE 
WHERE 
     (EMP_ID = EMPID 
      OR (EMP_ID IS NULL 
      AND EMPID IS NULL)) 
     AND (EMP_NAME = EMPNAME 
      OR (EMP_NAME IS NULL 
      AND EMPNAME IS NULL)) 
     AND (EMP_SAL = EMPSAL 
      OR (EMP_SAL IS NULL 
      AND EMPSAL IS NULL)); 

後更新我修改查詢類似下面，它被編譯，但給人運行時錯誤說ORA-00933：SQL命令不能正確地結束上只執行立即之前

V_SQL :='SELECT EMP_NAME INTO V_empname FROM employee WHERE '; 
    BEGIN 
    IF(EMPID IS NOT NULL) THEN 
    V_SQL := V_SQL || ' emp_id='||EMPID; 
    END IF; 
    IF(EMPNAME IS NOT NULL) THEN 
     V_SQL := V_SQL || ' AND emp_name='||EMPNAME; 
    END IF; 
    IF(V_empsalIS NOT NULL) THEN 
     V_SQL := V_SQL || ' AND emp_sal='||empsal; 
V_SQL := V_SQL ||' AND ACTIVE =''Y''' ; 
    END IF; 
     EXECUTE IMMEDIATE V_SQL; 
    EXCEPTION 
    WHEN NO_DATA_FOUND THEN 
     V_check:= '' ; 
    END; 

Answer 1

在這裏，你有另一種選擇：

V_SQL_WHERE := null; 

    V_SQL :='SELECT EMP_NAME INTO V_empname FROM employee'; 
    BEGIN 

    IF(EMPID IS NOT NULL) THEN 
     V_SQL_WHERE := V_SQL_WHERE || ' emp_id='||EMPID; 
    END IF; 

    IF(EMPNAME IS NOT NULL) THEN 

     IF (V_SQL_WHERE is not null) THEN 
     V_SQL_WHERE := V_SQL_WHERE || ' AND '; 
     END IF; 

     V_SQL_WHERE := V_SQL_WHERE || ' emp_name='||EMPNAME; 
    END IF; 

    IF(V_empsalIS NOT NULL) THEN 

     IF (V_SQL_WHERE is not null) THEN 
     V_SQL_WHERE := V_SQL_WHERE || ' AND '; 
     END IF; 
     V_SQL_WHERE := V_SQL_WHERE || ' emp_sal=' || empsal; 
     V_SQL_WHERE := V_SQL_WHERE || ' AND ACTIVE =''Y''' ; 

    END IF; 

    IF (V_SQL_WHERE is not null) then 
     V_SQL := V_SQL || ' WHERE ' || V_SQL_WHERE; 
    end if; 

     EXECUTE IMMEDIATE V_SQL; 
    EXCEPTION 
    WHEN NO_DATA_FOUND THEN 
     V_check:= '' ; 
    END; 

Answer 2

您可以從頭開始創建一個，包括if和elses，也可以使用名爲plsql-utils的包SQL_BUILDER_PKG。它爲你完成整個工作。

對SQL公用事業

http://code.google.com/p/plsql-utils/

如看：

declare 
    l_my_query sql_builder_pkg.t_query; 
    l_sql varchar2(32000); 
begin 

    sql_builder_pkg.add_select (l_my_query, 'ename'); 
    sql_builder_pkg.add_select (l_my_query, 'sal'); 
    sql_builder_pkg.add_select (l_my_query, 'deptno'); 
    sql_builder_pkg.add_from (l_my_query, 'emp'); 
    sql_builder_pkg.add_where (l_my_query, 'ename = :p_ename'); 
    sql_builder_pkg.add_where (l_my_query, 'sal > :p_sal'); 
    l_sql := sql_builder_pkg.get_sql (l_my_query); 
    dbms_output.put_line (l_sql); 
end; 

我用它在一個項目中，這是一個很好的工具。

Answer 3

事情是這樣的：（沒有測試，但只是一個想法）

BEGIN 
    IF EMPID IS NOT NULL 
    THEN 
     CLAUSE1 := 'EMP_ID = EMPID'; 
    ELSE 
     CLAUSE1 := '1=1'; 
    END IF; 

    IF EMPNAME IS NOT NULL 
    THEN 
     CLAUSE2 := 'EMP_NAME = EMPNAME'; 
    ELSE 
     CLAUSE2 := '1=1'; 
    END IF; 

    IF EMPSAL IS NOT NULL 
    THEN 
     CLAUSE3 := 'EMP_SAL = EMPSAL'; 
    ELSE 
     CLAUSE3 := '1=1'; 
    END IF; 

    IF ( EMPSAL IS NULL 
     AND EMPNAME IS NULL 
     AND EMPID IS NOT NULL) 
    THEN 
     CLAUSE1 := '1=0'; 
     CLAUSE2 := '1=0'; 

     CLAUSE3 := '1=0'; 
    END IF; 

    QUERY_STR := 
      ' SELECT EMP_NAME INTO V_EMP_NAME FROM EMPLOYEE WHERE' 
     || CLAUSE1 
     || ' AND ' 
     || CLAUSE2 
     || ' AND ' 
     || CLAUSE3; 
END;