How to transform a MSSQL CTE query to MySQL? - mysql

Question

in my MySQL schema, I have the category(id, parentid, name) table
In the MSSQL, I have that CTE query (to build a category tree from the bottom up for a supplied category ID:
with CTE (id, pid, name)
as
(
select id, parentid as pid,name
from category
where id = 197
union all
select CTE.pid as id , category.parentid as pid, category.name
from CTE
inner join category
on category.id = CTE.pid
)
select * from CTE
How to 'transform' that query to MySQL ?

Answer 1

Unfortunately MySQL doesn't support CTE (Common Table Expressions). This is long overdue IMO. Often, you can just use a subquery instead, but this particular CTE is recursive: it refers to itself inside the query. Recursive CTE's are extremely useful for hierarchical data, but again: MySql doesn't support them at all. You have to implement a stored procedure to get the same results.
A previous answer of mine should provide a good starting point:
Generating Depth based tree from Hierarchical Data in MySQL (no CTEs)

Answer 2

Thankfully it's not necessary anymore, as MySQL starting from 8.0.1 supports CTE.

Answer 3

unfortunately MYSQl or XAMPP(MARIADB) mysql doesnot support CTEs(COMMON TABLE EXPRESSIONS),
for the same you will have to use nested queries.
for more information click on the below link:-
https://mariadb.com/kb/en/library/with/

Answer 4

Please check what version of MySQL you have using SELECT VERSION();
If it is 8 or above you can then proceed further with my comment.
With MySQL 8.0, MariaDB 10.2, and later versions, you can use recursive CTEs:
WITH RECURSIVE CTE (id, pid, name) AS (
select id, parentid as pid,name
from category
where id = 197
union all
select CTE.pid as id , category.parentid as pid, category.name
from CTE
inner join category
on category.id = CTE.pid
)
select * from CTE ;
Note that CTEs are limited by cte_max_recursion_depth (default 1000, max 4,294,967,295 (2³²−1)) in MySQL and by max_recursive_iterations (default 4,294,967,295) in MariaDB.
You can increase the limit by executing:
SET cte_max_recursion_depth = 4294967295;
It will only affect your current session and won't be persisted.