如何使此 IF 语句跳到另一个 if 语句?

Question

如何使这个 If 语句跳到下面的 if 语句？我尝试了其他如果，然后，但它不起作用。我希望它显示，无论输入是否传递到变量中。

declare @sql varchar(8000)
declare @sql_where varchar(8000)
declare @ww varchar(10)
declare @plant varchar(10)
declare @plnr_id varchar(10)
set @plant = 'CS58'
set @ww = '201240'  
set @plnr_id = 'G37'
set @sql_where = 'where'
set @sql = 'select * from  rout_sub_doi '
if len(@plant) > 0 
set @sql_where = @sql_where + ' plant = ''' + @plant + ''' '
if len(@ww) > 0
set @sql_where = @sql_where + 'AND sys_intel_ww = ''' + @ww + ''' '
if len(@plnr_id) > 0 
set @sql_where = @sql_where + ' AND plnr_id = ''' + @plnr_id + ''' '

print @sql
print @sql_where
exec (@sql + @sql_where )

Answer 1

处理未知数量条件的常用方法是使第一个条件WHERE 1=1或良性，例如在已知 id 不可为空时WHERE id IS NOT NULL。

declare @sql varchar(8000)
declare @sql_where varchar(8000)
declare @ww varchar(10)
declare @plant varchar(10)
declare @plnr_id varchar(10)
set @plant = 'CS58'
set @ww = '201240'  
set @plnr_id = 'G37'
set @sql_where = ''
set @sql = 'select * from rout_sub_doi where 1=1 '
if len(@plant) > 0 
set @sql_where = @sql_where + 'AND plant = ''' + @plant + ''' '
if len(@ww) > 0
set @sql_where = @sql_where + 'AND sys_intel_ww = ''' + @ww + ''' '
if len(@plnr_id) > 0 
set @sql_where = @sql_where + 'AND plnr_id = ''' + @plnr_id + ''' '
print @sql
print @sql_where
exec (@sql + @sql_where )