oracle listagg替代wm |
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oracle listagg替代wm
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原sql：
select e.comment_id, e.evaluate_type, wmsys.wm_concat(evaluate_label) labels
from evaluating_label e
where exists(select *
from evaluation o
where o.order_id = '123' and e.comment_id = o.id)
group by e.comment_id, e.evaluate_type
效率极低，三万多条数据十多分钟都没查出来 替换listagg后 select e.comment_id, e.evaluate_type, listagg(e.EVALUATE_LABEL, ',') within group ( order by null) labels from evaluating_label e where exists (select * from evaluation o where o.order_id = '123' and e.comment_id = o.id) group by e.comment_id, e.evaluate_type;三秒内就出结果了。。。。 补充函数文档说明: listagg() String Aggregation Techniques 值得一提的是,WM_CONCAT在12c后的版本被删除掉了. |
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