Question

基于输入＆quot; include_child＆＃39;我可以选择哪里条件？

实际查询：

SELECT *
  FROM table1 t
WHERE t.node_id IN (SELECT decode(:include_Child , 1 ,child_node_id, 0 , 123) 
                             FROM table2 
                            WHERE node_id IN 123 )

寻找类似的东西：

IF include_Child = 0 then
SELECT *
  FROM table1 t
WHERE t.node_id IN 123 -- do no use table2 at all

-- only when condition met then use table2
IF include_Child = 1 then
SELECT *
  FROM table1 t
WHERE t.node_id IN (select child_node from table2)

我想在SELECT查询中使用它。不在PL / SQL块中。 DB版本是11g

有什么建议吗？

提前致谢！

Answer 1

如何使用and和or？

SELECT *
FROM table1 t
WHERE (:include_Child = 0 and t.node_id = 123) or
      (:include_Child = 1 and t.node_id IN (select child_node from table2) )

Answer 2

这是另一种方法。

SELECT *
FROM table1 t
WHERE t.node_id IN 123 -- do no use table2 at all
AND include_Child = 0
UNION ALL
SELECT *
FROM table1 t
WHERE t.node_id IN (select child_node from table2)
AND include_Child = 1

是否有类似于case语句但返回多行可以在SELECT查询中使用？

2 个答案: