How can I have multiple common table expressions in a single SELECT statement?
I am in the process of simplifying a complicated select statement, so thought I would use common table expressions.
Declaring a single cte works fine.
WITH cte1 AS (
SELECT * from cdr.Location
)
select * from cte1
Is it possible to declare and use more than one cte in the same SELECT?
ie this sql gives an error
WITH cte1 as (
SELECT * from cdr.Location
)
WITH cte2 as (
SELECT * from cdr.Location
)
select * from cte1
union
select * from cte2
the error is
Msg 156, Level 15, State 1, Line 7
Incorrect syntax near the keyword 'WITH'.
Msg 319, Level 15, State 1, Line 7
Incorrect syntax near the keyword 'with'. If this statement is a common table expression, an xmlnamespaces clause or a change tracking context clause, the previous statement must be terminated with a semicolon.
NB. I have tried putting semicolons in and get this error
Msg 102, Level 15, State 1, Line 5
Incorrect syntax near ';'.
Msg 102, Level 15, State 1, Line 9
Incorrect syntax near ';'.
Probably not relevant but this is on SQL 2008.
Solution 1:
I think it should be something like:
WITH
cte1 as (SELECT * from cdr.Location),
cte2 as (SELECT * from cdr.Location)
select * from cte1 union select * from cte2
Basically, WITH
is just a clause here, and like the other clauses that take lists, "," is the appropriate delimiter.
Solution 2:
Above mentioned answer is right:
WITH
cte1 as (SELECT * from cdr.Location),
cte2 as (SELECT * from cdr.Location)
select * from cte1 union select * from cte2
Aditionally, You can also query from cte1 in cte2 :
WITH
cte1 as (SELECT * from cdr.Location),
cte2 as (SELECT * from cte1 where val1 = val2)
select * from cte1 union select * from cte2
val1,val2
are just asumptions for expressions..
Hope this blog will also help : http://iamfixed.blogspot.de/2017/11/common-table-expression-in-sql-with.html