如何在 sql server 2008 的存储过程中使用 if 比较两个字符串？

Question

我想做这样的事情：

declare @temp as varchar
    set @temp='Measure'

if(@temp == 'Measure')
   Select Measure from Measuretable
else
   Select OtherMeasure from Measuretable

Answer 1

你想要的是一个 SQL case 语句。
它们的形式是：

  select case [expression or column]
  when [value] then [result]
  when [value2] then [result2]
  else [value3] end

或：

  select case 
  when [expression or column] = [value] then [result]
  when [expression or column] = [value2] then [result2]
  else [value3] end

在您的示例中，您需要：

declare @temp as varchar(100)
set @temp='Measure'

select case @temp 
   when 'Measure' then Measure 
   else OtherMeasure end
from Measuretable

Answer 2

declare @temp as varchar
  set @temp='Measure'
  if(@temp = 'Measure')
Select Measure from Measuretable
else
Select OtherMeasure from Measuretable

Answer 3

您也可以尝试使用此方法来匹配字符串。

DECLARE @temp1 VARCHAR(1000)
    SET @temp1 = '<li>Error in connecting server.</li>'
DECLARE @temp2 VARCHAR(1000)
    SET @temp2 = '<li>Error in connecting server. connection timeout.</li>'

IF @temp1 like '%Error in connecting server.%' OR @temp1 like '%Error in connecting server. connection timeout.%'
  SELECT 'yes'
ELSE
  SELECT 'no'

Answer 4

两件事：

1. 只需一 (1) 个等号即可计算
2. 您需要指定 VARCHAR 的长度 - 默认为单个字符。

---

使用：

DECLARE @temp VARCHAR(10)
    SET @temp = 'm'

IF @temp = 'm'
  SELECT 'yes'
ELSE
  SELECT 'no'

VARCHAR(10) 表示 VARCHAR 最多可容纳 10 个字符。更多行为示例 -

DECLARE @temp VARCHAR
    SET @temp = 'm'

IF @temp = 'm'
  SELECT 'yes'
ELSE
  SELECT 'no'

...将返回“是”

DECLARE @temp VARCHAR
    SET @temp = 'mtest'

IF @temp = 'm'
  SELECT 'yes'
ELSE
  SELECT 'no'

...将返回“否”。