Question

我有这个SQL查询：

DT <- 
  data.table(V1=paste("Day",1:5,sep="_"),V2=c(4,1,4,3,3),V3=c(4,1,5,4,2),V4=c(4,2,4,4,3))

给出了这个输出：

SELECT DISTINCT category FROM merchant ORDER BY category ASC

如何在结果的开头（或结尾）放置包含“general”的行？

Answer 1

在CASE子句中使用ORDER BY表达式：

SELECT category  
FROM (
  SELECT DISTINCT category 
  FROM merchant ) t
ORDER BY 
   CASE WHEN category = 'General' THEN 0 ELSE 1 END,
   category ASC

CASE保证首先排序General行。第二个参数按升序排序其余类别。

Answer 2

你可以试试这个：

SELECT category 
FROM  merchant 
WHERE category = 'general'
UNION
SELECT DISTINCT category 
FROM merchant
WHERE category NOT IN ('general')

如何在条件下订购SQL查询结果？

2 个答案: