基于表中值的动态SQL

Question

I need to dynamically create SQL, I have a table like this :

Operator  Value
BETWEEN   0 AND 21
BETWEEN   21 AND 50

I need to write a query that will basically execute:

SELECT * FROM tbl
WHERE 22 Operator Value

And this should return the second row of the table above.

Answer 1

You can go with this, give it a try

if object_id('tempdb..#Test') is not null drop table #Test
create table #Test (Operator nvarchar(20), Value nvarchar(20))

insert into #Test (Operator, Value)
values
('BETWEEN', '0 AND 21'),
('BETWEEN', '21 AND 50')

declare @sql nvarchar(max) = 'SELECT * FROM #Test WHERE 22 '

declare @sqlHelper nvarchar(max) = 
                (select Operator + ' ' + Value
                        + ' and Value = '''+Value+''''
                        from #Test 
                        where 22 <= Cast(RIGHT(Value, 2) as int) and
                              22 >= Cast(LEFT(Value, 2) as int))

select @sql + @sqlHelper 
execute (@sql + @sqlHelper)

rextester: http://rextester.com/OJTIW53082

query exectued is: SELECT * FROM #Test WHERE 22 BETWEEN 21 AND 50 and Value = '21 AND 50'

results:

+----------+-----------+
| Operator |   Value   |
+----------+-----------+
| BETWEEN  | 21 AND 50 |
+----------+-----------+