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  • Oracle 游标的各种写法

    -- for .. in `隐式游标`
    
    
    BEGIN
    FOR RS IN (SELECT column_1 FROM table_name) LOOP
    dbms_output.put_line(RS.column_1);
    END LOOP;
    END;
    
    
    
    -- RS 必须是单个字段
    
    DECLARE
    CURSOR RS IS SELECT column_1 FROM table_name;
    column_1 VARCHAR2(50);
    BEGIN
    OPEN RS;
    LOOP
    FETCH RS INTO column_1;
    EXIT WHEN RS%NOTFOUND;
    dbms_output.put_line(column_1);
    END LOOP;
    CLOSE RS;
    END;
    /
    
    
    -- bulk collect显示游标
    
    DECLARE
    CURSOR RS IS SELECT column_1 FROM table_name;
    column_1_array dbms_sql.Varchar2_Table;
    BEGIN
    OPEN RS;
    FETCH RS BULK COLLECT INTO column_1_array;
    FOR i IN 1 .. column_1_array.count LOOP
    dbms_output.put_line(column_1_array(i));
    END LOOP;
    CLOSE RS;
    END;
    
    
    -- bulk collect 显示游标 + limit
    
    DECLARE
    CURSOR RS IS SELECT column_1 FROM table_name;
    column_1_array dbms_sql.Varchar2_Table;
    BEGIN
    OPEN RS;
    LOOP
    FETCH RS BULK COLLECT INTO column_1_array LIMIT 2;
    EXIT WHEN RS%NOTFOUND;
    FOR i IN 1 .. column_1_array.count LOOP
    dbms_output.put_line(column_1_array(i));
    END LOOP;
    END LOOP;
    CLOSE RS;
    END;
    
    
    - select into 隐式游标
    
    DECLARE
    column_1 VARCHAR2(100);
    BEGIN
    SELECT zone_code INTO column_1 FROM table_name WHERE ROWNUM = 1;
    dbms_output.put_line(column_1);
    END;
    
    
    
    - 动态sql,select into 隐式游标
    
    DECLARE
    column_1 VARCHAR2(50);
    l_table VARCHAR2(200);
    l_sql VARCHAR2(200);
    BEGIN
    l_table := 'table_name';
    l_sql := 'select column_1 from ' || l_table || ' where rownum = 1';
    EXECUTE IMMEDIATE l_sql INTO column_1;
    dbms_output.put_line(column_1);
    END;
    
    
    - 动态sql select into 隐式游标 + bulk collect
    
    DECLARE
    column_1_array dbms_sql.Varchar2_Table;
    l_table VARCHAR2(20);
    l_sql VARCHAR2(100);
    BEGIN
    l_table := 'table_name';
    l_sql := 'select column_1 from ' || l_table;
    EXECUTE IMMEDIATE l_sql BULK COLLECT INTO column_1_array;
    FOR i IN 1 .. column_1_array .count LOOP
    dbms_output.put_line(column_1_array(i));
    END LOOP;
    END;
    

      

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  • 原文地址:https://www.cnblogs.com/fubinhnust/p/9928881.html
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