△我们常遇到一个存储过程要做都种排序的情况...... 我们常遇到一个存储过程要做都种排序的情况。通常order by 的条件只有一个固定的,这是远远不够的。需要用一个变量来替换它,而Oracle有不能识别Order by后面的字符串。该怎么办呢?先看看我的一个糟糕方案: IF myorderby='OBJECTID DESC' then --按名称排序 OPEN outcur FOR SELECT * FROM( SELECT rownum rowno,t.* FROM ( SELECT OBJECTID , HITS,POSTTIME FROM CARTOON ORDER BY OBJECTID DESC) t WHERE rownum elsif myorderby='HITS DESC' then --按点击率排序 OPEN outcur FOR SELECT * FROM( SELECT rownum rowno,t.* FROM ( SELECT OBJECTID , HITS,POSTTIME FROM CARTOON ORDER BY HITS DESC') t WHERE rownum else --按时间排序 OPEN outcur FOR SELECT * FROM( SELECT rownum rowno,t.* FROM ( SELECT OBJECTID , HITS,POSTTIME FROM CARTOON ORDER BY HITS DESC') t WHERE rownum END IF; 这虽然是通常使用的两种排序方式得以功过,但显得繁杂而且不够通用。 这时我的同事的好办法: --------------------------------------------------- IF (myorderby is not null) then mysql:='SELECT * FROM( SELECT rownum rowno,t.* FROM ( SELECT OBJECTID , HITS,POSTTIME FROM CARTOON ORDER BY '|| myorderby || ') t WHERE rownum<' || endRow || ') WHERE rowno>=' || startRow; else mysql:='SELECT * FROM( SELECT rownum rowno,t.* FROM ( SELECT OBJECTID , HITS,POSTTIME FROM CARTOON ORDER BY posttime DESC) t WHERE rownum<' || endRow || ') WHERE rowno>=' || startRow; END IF; OPEN outcur FOR mysql; 怎么样,感觉不同凡响吧。希望你能有更好的办法。 |
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