Oracle解析来自clob的标记之间的数据

<start>This is the first part.</start><middle>This is the middle part.</middle><end>This is the end part.</end>

DECLARE
    v_clob CLOB;
    v_start_pos NUMBER;
    v_end_pos NUMBER;
    v_result VARCHAR2(4000);
BEGIN
    -- 假设v_clob已经包含了上述内容
    v_clob := '<start>This is the first part.</start><middle>This is the middle part.</middle><end>This is the end part.</end>';

    -- 查找<start>的位置
    v_start_pos := DBMS_LOB.INSTR(v_clob, '<start>') + LENGTH('<start>');
    -- 查找<middle>的位置
    v_end_pos := DBMS_LOB.INSTR(v_clob, '<middle>');

    -- 提取之间的数据
    IF v_start_pos > 0 AND v_end_pos > 0 THEN
        v_result := SUBSTR(v_clob, v_start_pos, v_end_pos - v_start_pos);
        DBMS_OUTPUT.PUT_LINE('Result: ' || v_result);
    ELSE
        DBMS_OUTPUT.PUT_LINE('Markers not found.');
    END IF;
END;
/