Question

我有一个适合你的基本款。我在下面的语句中打破了语法。我不知道如何在一个语句中运行两个'case'选项。我收到错误：找不到FROM关键字。

SELECT
    CASE
        WHEN`enter code here`
            attr.UDA_AUTO_KEY = 40
                THEN
                    'Parts Sales'
        ELSE
            'This is blank'
    END AS Parts Sales,
    CASE
        WHEN
            attr.UDA_AUTO_KEY = 5
                THEN
                    'Aircraft Management'
        ELSE
            'This is blank'
    END AS Aircraft Management,
    cmp.COMPANY_NAME, cmp.ADDRESS1
FROM COMPANIES cmp
LEFT JOIN UDA_CHECKED uda ON uda.AUTO_KEY = cmp.CMP_AUTO_KEY
LEFT JOIN USER_DEFINED_ATTRIBUTES attr ON uda.UDA_AUTO_KEY = attr.UDA_AUTO_KEY
WHERE attr.AUTO_KEY_PREFIX = 'CMP'

Answer 1

问题不在CASE中，而在列别名中。如果您需要带空格的别名，则必须使用双引号：

SELECT
    CASE
        WHEN
            attr.UDA_AUTO_KEY = 40
                THEN
                    'Parts Sales'
        ELSE
            'This is blank'
    END AS "Parts Sales",
    CASE
        WHEN
            attr.UDA_AUTO_KEY = 5
                THEN
                    'Aircraft Management'
        ELSE
            'This is blank'
    END AS "Aircraft Management",
   ...

否则，只需删除空格：

SELECT
    CASE
        WHEN
            attr.UDA_AUTO_KEY = 40
                THEN
                    'Parts Sales'
        ELSE
            'This is blank'
    END AS PartsSales,
    CASE
        WHEN
            attr.UDA_AUTO_KEY = 5
                THEN
                    'Aircraft Management'
        ELSE
            'This is blank'
    END AS AircraftManagement,
    ...

Answer 2

更新

使用双引号"汇总列别名。

整个声明：

SELECT
  CASE WHEN attr.UDA_AUTO_KEY = 5 THEN 'Aircraft Management' 
       ELSE 'This is blank' END AS "Aircraft Management",
  CASE WHEN attr.UDA_AUTO_KEY = 40 THEN 'Parts Sales' 
       ELSE 'This is blank' END AS "Parts Sales",
  cmp.COMPANY_NAME, 
  cmp.ADDRESS1
FROM COMPANIES cmp
LEFT JOIN UDA_CHECKED uda ON uda.AUTO_KEY = cmp.CMP_AUTO_KEY
LEFT JOIN USER_DEFINED_ATTRIBUTES attr ON uda.UDA_AUTO_KEY = attr.UDA_AUTO_KEY
WHERE attr.AUTO_KEY_PREFIX = 'CMP'

此外，如果没有匹配项，请考虑删除ELSE部分并将列值保留为NULL，而不是放置This is blank值。

SQL中的多个Case语句

2 个答案: