Question

DECLARE @step VARCHAR(25) = '15';
DECLARE @COL VARCHAR(50) = step_col_@step;
UPDATE table_tblName SET @COL=<some value> WHERE <condition>

我有上述查询，其中@COL应该是动态的，即step_col_1，step_col_2，step_col_3 ...... step_col_18。如果没有在sql server中使用If-else条件，我该如何实现呢？

Answer 1

尝试以下查询，

body {
  border: 1px solid;
  padding: 0 auto;
}

header {
  height: 25%;
  border-bottom: 1px solid;
}

header #logo {
  float: left;
  text-align: center;
  width: 25%;
}

header #titre {
  background: black;
  color: white;
  float: right;
  text-align: center;
  width: 75%;
}

#xd {}

nav {
  width: 25%;
  text-align: center;
  float: left;
}

section {
  
  width: 75%;
  float: right;
  text-align: center;
}

.clr {
  clear: both;
}

Answer 2

传递这样的变量以形成动态sql查询

DECLARE @step VARCHAR(25) = '15';
DECLARE @COL VARCHAR(50) = 'step_col_'+@step
exec ('UPDATE table_tblName SET '+@COL+'=<some value> WHERE <condition>')

Answer 3

 DECLARE @step VARCHAR(25) = '15';
 DECLARE @COL VARCHAR(50) = 'step_col_'+@step;
 DECLARE @String VARCHAR(500) = ''
 SET @String = 'UPDATE table_tblName SET '''+@COL+''' = <some value> WHERE  
 <condition>' 
 EXEC (@String)

Answer 4

DECLARE @step VARCHAR(25) = '15';
DECLARE @COL VARCHAR(50) 
SET @COL = 'step_col'+@step;

UPDATE table_tblName SET @COL=<some value> WHERE <condition>

在sql server中映射动态列名

4 个答案: