Question

我需要一个允许部分匹配的case语句。我收到语法错误，但我想知道是否有类似的东西是可能的。如果没有，我的辅助解决方案是重写为光标... 例如：

SELECT CASE ColumnName
           WHEN 'value1' THEN 'answer1'
           WHEN 'value2' THEN 'answer2'
           WHEN LIKE '%TEST%' THEN 'answer3'
       END AS Answer
FROM TableName

Answer 1

试试这个

SELECT CASE 
           WHEN ColumnName = 'value1' THEN 'answer1'
           WHEN ColumnName = 'value2' THEN 'answer2'
           WHEN ColumnName LIKE '%TEST%' THEN 'answer3'
       END AS Answer
FROM TableName

例如你可以运行

SELECT name,CASE 
           WHEN Name = 'sysobjects' THEN 'answer1'
           WHEN Name = 'syscols' THEN 'answer2'
           WHEN Name LIKE '%p%' THEN 'answer3'
           ELSE 'unknown'
       END AS Answer
FROM sysobjects

Answer 2

需要使用略有不同的CASE语法：

SELECT CASE WHEN ColumnName LIKE 'value1' THEN 'answer1'
            WHEN ColumnName LIKE 'value2' THEN 'answer2'
            WHEN ColumnName LIKE '%TEST%' THEN 'answer3'
ELSE 'not like any of them' END [Answer]
FROM TableName

Answer 3

或者，您可以嵌套CASE条件和CASE WHEN值子句，如下所示：

SELECT CASE ColumnName
           WHEN 'value1' THEN 'answer1'
           WHEN 'value2' THEN 'answer2'
           ELSE CASE WHEN ColumnName LIKE '%TEST%' THEN 'answer3' END
       END AS Answer
FROM TableName

Answer 4

您使用的是“简单CASE表达式”，但您应该使用“已搜索的CASE表达式”。有关示例，请参阅the documentation。

Answer 5

在sql ORACLE 10中

SELECT 
    CASE WHEN instr(ColumnName, 'value1')>0 THEN 'answer1'
       WHEN instr(ColumnName,'value2')>0 THEN 'answer2'
       WHEN instr(ColumnName,'TEST')>0 THEN 'answer3'
       ELSE 'not like any of them' 
    END
FROM TableName

SQL 2005我可以在case语句中使用关键字

5 个答案: