Question

我有一个类似于下面显示的SQL查询

SELECT col1 AS 'Column 1', SUM(ROUND(col2, 2)) AS 'Column 2'
FROM db.dbo.table
GROUP BY col1

这是在PHP脚本中运行的，用于生成JSON。第1列是浮点类型，第1列中的大块数据是0.我希望每当第1列中的值为0时，它将其替换为UNKNOWN。例如。我上面的查询将输出类似的内容

------------------------------
|0            |142563        |
------------------------------
|1            |348           |
------------------------------
|2            |2535          |
------------------------------
|3            |32            |
------------------------------
|4            |82536         |
------------------------------
|5            |12            |
------------------------------

我希望它像这样

------------------------------
|UNKNOWN      |142563        |
------------------------------
|1            |348           |
------------------------------
|2            |2535          |
------------------------------
|3            |32            |
------------------------------
|4            |82536         |
------------------------------
|5            |12            |
------------------------------

有人可以帮帮我吗？谢谢！

Answer 1

您想使用case声明：

SELECT (case when col1 = 0 then 'Unknown' else cast(col1 as varchar(255)) end) AS 'Column 1', 
       SUM(ROUND(col2, 2)) AS 'Column 2'
FROM db.dbo.table
GROUP BY col1;

我还添加了一个明确的cast()，因为col1是一个浮点数。

如果要控制格式，请使用str()。也许：

SELECT (case when col1 = 0 then 'Unknown' else str(col1, 6, 2) end) AS 'Column 1', 
       SUM(ROUND(col2, 2)) AS 'Column 2'
FROM db.dbo.table
GROUP BY col1;

Answer 2

使用TSQL CASE声明

SELECT CASE WHEN col1 = 0 THEN 'Unknown' ELSE Col1 END AS 'Column 1', SUM(ROUND(col2, 2)) AS 'Column 2'
FROM db.dbo.table
GROUP BY col1

Answer 3

在SQL Server 2012中，您可以执行

SELECT IIF(col1 = 0, 'UNKNOWN', cast(col1 as varchar(100)))AS 'Column 1', SUM(ROUND(col2, 2)) AS 'Column 2' 
FROM table
GROUP BY col1;

将值从0更改为“UNKNOWN”

3 个答案: