Sql ，…在单行中。编辑我的答案现在检查我对该文档的阅读是-选择RAND（）作为col，col+1作为col2被视为选择RAND（）作为col，RAND（）+1作为col2或通常选择（某些表达式）作为col，（某些表达式）+1作为col2我对该文档的理解是-正如

---

，…在单行中。编辑我的答案现在检查我对该文档的阅读是-

选择RAND（）作为col，col+1作为col2

被视为

选择RAND（）作为col，RAND（）+1作为col2

或通常

选择（某些表达式）作为col，（某些表达式）+1作为col2

我对该文档的理解是-正如您所看到的-

选择RAND（）作为col，col+1作为col2

被视为

选择RAND（）作为col，RAND（）+1作为col2

或通常

选择（某些表达式）作为col，（某些表达式）+1作为col2

您的整个参数依赖于多次重复使用同一列别名；看起来这才是真正糟糕的做法。您的整个论点都建立在多次重复使用同一列别名的基础上；看来这才是真正的坏习惯。

select clicks / impressions as probability, 
        round(100 * probability, 1) as percentage from raw_data;

select 1 AS col
      ,col + 1 AS col2;

select RAND() AS col
      ,col + 1 AS col2

-- if RAND() returns 0.5 then I would expect
-- 0.5 and 1.5

-- I get: 0.3 and 1.7
-- it means that the query was evaluated as:
select RAND() AS col,
       RAND() + 1 AS col2

SELECT s.col, s.col+1 AS col2
FROM t ,LATERAL (SELECT RANDOM()) AS s(col)  
-- 0.19089933477628307  1.190899334776283

      With Data
       As (Select count( *) from table)

       Select Data+1, Data from table

select (a + 1) as b, b 
from (select 1 as a, 0 as b) x;

select (a + 1) as b, calculated b, b
from (select 1 as a, 0 as b) x;