Question

DECLARE
    CURSOR cursor IS SELECT SHIP_ID, DATE_ARRIVE, QTY_EXPECTED, DESCRIPTION, QTY_HAND, ITEM_RATE, (QTY_EXPECTED * ITEM_RATE), ((QTY_EXPECTED * ITEM_RATE) + (QTY_HAND * ITEM_RATE)),((QTY_EXPECTED * ITEM_RATE) + (QTY_HAND * ITEM_RATE))
    FROM SHIPPINGTABLE;
    S_SHIPID SHIPPINGTABLE.SHIP_ID%TYPE;
    S_DATEARRIVE SHIPPINGTABLE.DATE_ARRIVE%TYPE;
    S_QTYEXPECTED SHIPPINGTABLE.QTY_EXPECTED%TYPE;
    S_DESCRIPTION SHIPPINGTABLE.DESCRIPTION%TYPE;
    S_QTYHAND SHIPPINGTABLE.QTY_HAND%TYPE;
    S_ITEMRATE SHIPPINGTABLE.ITEM_RATE%TYPE;
    S_SHIPMENTVALUE NUMBER(10);
    S_TOTALVALUE NUMBER(10);
    S_GRANDTOTAL NUMBER(10) := 0;
BEGIN
    OPEN cursor;
        LOOP
        FETCH CURSOR INTO S_SHIPID, S_DATEARRIVE, S_QTYEXPECTED, S_DESCRIPTION, S_QTYHAND, S_ITEMRATE, S_SHIPMENTVALUE, S_TOTALVALUE, S_GRANDTOTAL;
        EXIT WHEN cursor%NOTFOUND;
        DBMS_OUTPUT.PUT_LINE('Shipment ' || S_SHIPID || ' is expected to arrive on '|| S_DATEARRIVE);
        DBMS_OUTPUT.PUT_LINE('Description: ' || S_DESCRIPTION);
        DBMS_OUTPUT.PUT_LINE('Shipment value: ' || S_SHIPMENTVALUE);
        DBMS_OUTPUT.PUT_LINE('Quantity on hand: ' || S_QTYHAND);
        DBMS_OUTPUT.PUT_LINE('Total product value: ' || S_TOTALVALUE);
        DBMS_OUTPUT.PUT_LINE(CHR(10));
        S_GRANDTOTAL := S_TOTALVALUE + S_GRANDTOTAL;
        END LOOP;
        DBMS_OUTPUT.PUT_LINE(S_GRANDTOTAL);
        CLOSE cursor;
END;
/

我正在计算总计。现在输出如下

Shipment 211 is expected to arrive on 15-Nov-07
Description: Season Tents
Shipment value: 12500.
Quantity on hand: 3
Total product value: 14000

每个项目都是正确的。它还输出S_GRANDTOTAL，但它只将最后一项添加到自身，因此它不会添加前一项的总计。我知道在java中你可以做类似

的事情

variable += variable

有没有办法在sql中执行此操作？

Answer 1

与Java相同的PL / SQL [variable1 + = variable2]是[variable1：= variable1 + variable2]。所以乍一看，你的[S_GRANDTOTAL：= S_TOTALVALUE + S_GRANDTOTAL]看起来是正确的。但是，在SQL语句中，GRANDTOTAL的源派生与TOTAL_VALUE [（（QTY_EXPECTED * ITEM_RATE）+（QTY_HAND * ITEM_RATE））]的源派生相同。从SQL语句中删除最后一个字段定义，从游标提取语句中删除[[INTO] S_GRANDTOTAL]元素，我认为您的代码将按预期工作; TOTAL_VALUE将从零到最终累积地添加到S_GRAND_TOTAL变量，并显示在报告的末尾。

如果您在SQL语句中为派生字段设置别名，那将会很有帮助，例如：SELECT SHIP_ID，DATE_ARRIVE，QTY_EXPECTED，DESCRIPTION，QTY_HAND，ITEM_RATE，（QTY_EXPECTED * ITEM_RATE） AS SHIPMENT_VALUE ，（（QTY_EXPECTED * ITEM_RATE）+（QTY_HAND * ITEM_RATE）） AS TOTAL_VALUE

像这样的PL / SQL游标循环是不可扩展的，也就是说，如果表包含数百万或数十亿行和/或系统上存在高活动，它将使您的系统陷入困境。 /> 出于这个原因，我建议在前端使用报告工具，在后端使用单个SQL（不是PL / SQL游标循环）语句。让工具执行多级细节，聚合和汇总。

循环期间为self添加值

1 个答案: