Question

嵌套的case语句或cypher中的Decode或Map是否有任何方法？

Case when  object1 = 'Animal'
       then case when object2 = 'CAT' then 1 else 0
                 when object2 = 'RAT' then 2 else 0
       else -9 end 
 end

没有语法问题，但是内部的值不会传递给外壳。甚至试了一个变量别名。我甚至尝试过以下方法：

case object1 = 'Animal'
      when object2 = 'CAT' then 1 
      when object2 = 'RAT' then 2
 end

这甚至都不起作用。作为＆＃34; case object1 =＆＃39; Animal＆＃39;＆＃34;不被视为IF条件....只在WHEN中猜测。

Answer 1

如果使用嵌套案例：

UNWIND ['Human', 'Animal'] as var1
UNWIND ['CAT', 'RAT'] as var2
RETURN var1, var2,
       CASE WHEN var1 = 'Animal'
              THEN CASE WHEN var2 = 'CAT'
                          THEN 1
                        ELSE CASE WHEN var2 = 'RAT'
                                    THEN 2
                                  ELSE 0
                             END
                   END
            ELSE -9
       END as result

或者你可以使用map：

WITH  
     { Human: {
         __default: 101
       }, 
       Animal: {
         CAT: 1,
         RAT: 2,
         __default: 0
       },
       __default: -9
     } as tree
 UNWIND ['Human', 'Animal', 'Object'] as var1
 UNWIND ['RAT', 'CAT', 'DOG'] as var2
 RETURN var1, var2,
        CASE WHEN tree[var1] IS NULL THEN tree.__default 
             ELSE CASE WHEN tree[var1][var2] IS NULL THEN tree[var1].__default 
                       ELSE tree[var1][var2]
                  END
        END as result

Neo4j Cypher：嵌套的case语句

1 个答案: