[MDEV-24089] support oracle syntax: rownum - Jira

Details

Type: Task
Status: Closed (View Workflow)
Priority: Major
Resolution: Fixed
Fix Version/s: 10.6.1
Component/s: Optimizer, Server
Labels:
- oracle
- rownum

Description

Oracle ROWNUM is a pseudocolumn (not a real column) that is generated
when running a select.

ROWNUM will be assigned the numbers 1, 2, 3, 4, ... N.

For each row combination returned by a query, ROWNUM returns a number indicating the order in which Oracle selects the rows from the table (tables)

The first row combination selected has a ROWNUM of 1, the second has 2, and so
on.

When used in a sub query, the subquery will generate a new ROWNUM sequence for
each sub query execution.

The ROWNUM pseudocolumn should be implemented under SQL_MODE=ORACLE.

In many cases one could also replace WHERE ROWNUM <= X with LIMIT X.

The most common usage of rownum is to limit the number of rows in the query:

SELECT * from table where rownum < 10;

Examples:

create table t1 (a int primary key);

create table t2 (b int primary key);

insert into t1 values(1),(2),(3);

insert into t2 values(1),(2),(3);

select t1.a, (select t2.b from t2 where t1.a=t2.b and rownum < t1.a) from t1;

The following query is undefined (can return any rows) as rownum is generated before ORDER BY is done and there is no guarantee in which order the database is returning rows.

Select * from t1 order by t1.a desc having rownum <= 2;

Authentic Oracle behavior:

Prepare the data
create table t1(c1 number, c2 number);
create table t2(c1 number, c2 number);
create table t3(c1 number, c2 number);

insert into t1 values(1,1);
insert into t1 values(2,2);
insert into t1 values(3,3);

insert into t2 values(1,1);
insert into t2 values(2,2);
insert into t2 values(3,3);

insert into t3 values(1,1);
insert into t3 values(2,2);
insert into t3 values(3,3);

Run queries
SQL> select * from t1 where rownum<2;
C1 C2
1 1

SQL> select t1.c1, t1.c2 ,rownum from t1 left join t2 on t1.c1=t2.c1 inner join t3 on t2.c1=t3.c1;

C1 C2 ROWNUM
---------- ---------- ----------
1 1 1
2 2 2
3 3 3

SQL> select * from ( select t1.* , rownum row_id from t1 where rownum <= 5 ) where row_id > 2;

C1 C2 ROW_ID
---------- ---------- ----------
3 3 3


SQL> select t1.c1, (select t2.c2 from t2 where t1.c1=t2.c2 and rownum < t1.c1) from t1;

C1 (SELECTT2.C2FROMT2WHERET1.C1=T2.C2ANDROWNUM<T1.C1)
---------- --------------------------------------------------
1
2 2
3 3

One can also use ROWNUM with UPDATE:

UPDATE table SET column = ROWNUM;

In case of group by queries, the rownum will work on the originally found rows, not the result rows like LIMIT

SELECT sum(c1) FROM t1 WHERE rownum<=2;

This will return 3 (or at least not 6)

ROWNUM cannot be used with HAVING (Oracle has the same restriction)
ROWNUM should not be used in applications with the following constructs as the result will not be deterministic (it's legal to use it, but the rows used in the result set will differ based on engine or used optimizations):

In ON expressions
With GROUP BY
SELECT without an ORDER BY (This is a common case how ROWNUM is used and in this case we can replace it with LIMIT)

oracle rownum reference: https://docs.oracle.com/en/database/oracle/oracle-database/19/sqlrf/ROWNUM-Pseudocolumn.html#GUID-2E40EC12-3FCF-4A4F-B5F2-6BC669021726

Architecture:
Add function ROWNUM() (Item_rownum()).

Map the result of ROWNUM() to 'last_join->accepted_records', which is incremented for each row added to the result set.
This variable will be incremented in end_send(), end_send_group(), end_update() and end_unique_update()
Filesort() needs each own variable that is incremented for each accepted row.

In oracle mode, if field with name 'rownum' is used and there is no match in
any of the tables, map the field to Item_rownum()

Things to consider and test in addition to the test in the suggested patch:

Limit optimization
- If we have ROWNUM < # or ROWNUM <= # on the top level of the WHERE clause
  this should be converted to LIMIT. This is to be done in the
  JOIN::prepare phase(), probably after optimize_cond() which does
  propagate_cond_constants()
When using sum functions, it's not sent rows, it's examined rows we have to
limit against
Filesort, when done over single table needs it's own handling
(as there are no 'send_records' here). Limit is done according to found rows,
not sorted order.
Ensure that ROWNUM also works with UPDATE and DELETE
UNION
- ROWNUM should work independently for each UNION

Attachments

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10.5.6-rownum.patch
107 kB
2020-11-02 08:07
rownum.result
6 kB
2020-11-03 11:34
rownum.test
5 kB
2020-11-03 11:34

Issue Links

blocks

MDEV-20020 sql_mode="oracle" does not support "rownum" pseudo column

Open

causes

MDEV-26329 Equality operator does not work with ROWNUM() function after first row

Closed

MDEV-29129 Performance regression starting in 10.6: unlimited "select order by limit" always using temporary, taking between 60x and 2000x longer in 10.6, 10.7, and 10.8 than in 10.5

Closed

is duplicated by

MDEV-19782 sql_mode=ORACLE: ROWNUM

Closed

relates to

MDEV-27745 order by with incremented variable behaviour is different in 10.6

Closed

Activity

Ascending order - Click to sort in descending order

woqutech added a comment - 2020-11-02 08:07

we have implement a version of rownum, but it is not suitable for the following scenarios:

in the case of sub-query, we must set condition_pushdown_for_derived=off, derived_merge=off to keep the result the same with mariadb.
the current implementation has much restrictions in Nested subquery. like `select * from ( select t1.* , rownum row_id from t1 where rownum <= 5 ) where row_id > 2 `;
The current query result order is unstable
The current implementation with return error `ERROR 1052 (23000): Column'rownum' in field list is ambiguous` if there are multiple tables join. For example: `select t1.c1, t1.c2 ,rownum from t1 left join t2 on t1.c1=t2.c1 inner join t3 on t2.c1=t3.c1;` 10.5.6-rownum.patch

woqutech added a comment - 2020-11-02 08:07 we have implement a version of rownum, but it is not suitable for the following scenarios: in the case of sub-query, we must set condition_pushdown_for_derived=off, derived_merge=off to keep the result the same with mariadb. the current implementation has much restrictions in Nested subquery. like `select * from ( select t1.* , rownum row_id from t1 where rownum <= 5 ) where row_id > 2 `; The current query result order is unstable The current implementation with return error `ERROR 1052 (23000): Column'rownum' in field list is ambiguous` if there are multiple tables join. For example: `select t1.c1, t1.c2 ,rownum from t1 left join t2 on t1.c1=t2.c1 inner join t3 on t2.c1=t3.c1;` 10.5.6-rownum.patch

woqutech added a comment - 2020-11-03 11:33 - edited

test result on oracle

create table t1(c1 number, c2 number);

create table t2(c1 number, c2 number);

create table t3(c1 number, c2 number);

insert into t1 values(1,1);

insert into t1 values(2,2);

insert into t1 values(3,3);

insert into t2 values(1,1);

insert into t2 values(2,2);

insert into t2 values(3,3);

insert into t3 values(1,1);

insert into t3 values(2,2);

insert into t3 values(3,3);

SQL> select t1.c1, t1.c2 ,rownum from t1 left join t2 on t1.c1=t2.c1 inner join t3 on t2.c1=t3.c1;

C1 C2 ROWNUM
---------- ---------- ----------
1 1 1
2 2 2
3 3 3

SQL> select * from ( select t1.* , rownum row_id from t1 where rownum <= 5 ) where row_id > 2;

C1 C2 ROW_ID
---------- ---------- ----------
3 3 3


SQL> select t1.c1, (select t2.c2 from t2 where t1.c1=t2.c2 and rownum < t1.c1) from t1;

C1 (SELECTT2.C2FROMT2WHERET1.C1=T2.C2ANDROWNUM<T1.C1)
---------- --------------------------------------------------
1
2 2
3 3

woqutech added a comment - 2020-11-03 11:33 - edited test result on oracle create table t1(c1 number, c2 number); create table t2(c1 number, c2 number); create table t3(c1 number, c2 number); insert into t1 values (1,1); insert into t1 values (2,2); insert into t1 values (3,3); insert into t2 values (1,1); insert into t2 values (2,2); insert into t2 values (3,3); insert into t3 values (1,1); insert into t3 values (2,2); insert into t3 values (3,3); SQL> select t1.c1, t1.c2 ,rownum from t1 left join t2 on t1.c1=t2.c1 inner join t3 on t2.c1=t3.c1; C1 C2 ROWNUM ---------- ---------- ---------- 1 1 1 2 2 2 3 3 3 SQL> select * from ( select t1.* , rownum row_id from t1 where rownum <= 5 ) where row_id > 2; C1 C2 ROW_ID ---------- ---------- ---------- 3 3 3 SQL> select t1.c1, (select t2.c2 from t2 where t1.c1=t2.c2 and rownum < t1.c1) from t1; C1 (SELECTT2.C2FROMT2WHERET1.C1=T2.C2ANDROWNUM<T1.C1) ---------- -------------------------------------------------- 1 2 2 3 3

woqutech added a comment - 2020-11-03 11:34

add testcase file
rownum.result rownum.test

woqutech added a comment - 2020-11-03 11:34 add testcase file rownum.result rownum.test

woqutech added a comment - 2020-11-03 11:43 - edited

The most common usage of rownum (paste from rownum.result) is:

SET SQL_MODE='oracle';

set optimizer_switch='condition_pushdown_for_derived=off,derived_merge=off';

create database test_db1;

create table t1(c1 int, c2 varchar2(20), c3 timestamp(6), c4 varchar2(2));

create table t2(c1 int, c2 char(20), c3 int, c4 varchar2(2));

insert into t1 values(1, 'jim', '1984-08-21 18:00:00', '1');

insert into t1 values(2, 'menny','1986-10-02 20:20:00', '1');

insert into t1 values(3, 'linda', '1986-11-02 20:00:00', '1');

insert into t1 values(4, 'shory','1986-10-01 00:20:00', '0');

insert into t1 values(5, 'xuying', '1986-10-02 10:00:00', '1');

insert into t1 values(6, 'xujun', '1988-10-02 00:00:00', '0');

insert into t1 values(7, 'taoju', '1981-10-02 11:20:00', '1');

insert into t1 values(8, 'beibei', '1981-11-02 00:00:00', '1');

insert into t2 values(1, 'jim', 3, '0');

insert into t2 values(1, 'jim', 2, '1');

insert into t2 values(1, 'jim', 1, '1');

insert into t2 values(2, 'menny', 2, '1');

insert into t2 values(2, 'menny', 2, '1');

insert into t2 values(2, 'menny', 2, '1');

insert into t2 values(2, 'menny', 3, '0');

insert into t2 values(3, 'linda', 3, '1');

insert into t2 values(3, 'linda', 4, '1');

insert into t2 values(4, 'shory', 2, '1');

insert into t2 values(4, 'shory', 3, '0');

insert into t2 values(5, 'xuying', 1, '0');

insert into t2 values(5, 'xuying', 1, '0');

insert into t2 values(7, 'taoju', 3, '0');

select * from t1;

c1	c2	c3	c4

1	jim	x.000000	1

2	menny	x.000000	1

3	linda	x.000000	1

4	shory	x.000000	0

5	xuying	x.000000	1

6	xujun	x.000000	0

7	taoju	x.000000	1

8	beibei	x.000000	1

select * from t2;

c1	c2	c3	c4

1	jim	3	0

1	jim	2	1

1	jim	1	1

2	menny	2	1

2	menny	2	1

2	menny	2	1

2	menny	3	0

3	linda	3	1

3	linda	4	1

4	shory	2	1

4	shory	3	0

5	xuying	1	0

5	xuying	1	0

7	taoju	3	0

###############################################

"common test for rownum"

select c1, c2, rownum from t1;

c1	c2	rownum

1	jim	1

2	menny	2

3	linda	3

4	shory	4

5	xuying	5

6	xujun	6

7	taoju	7

8	beibei	8

select c1, c2, rownum from t1 where rownum = 1;

c1	c2	rownum

1	jim	1

select c1, c2, rownum from t1 where rownum >= 1;

c1	c2	rownum

1	jim	1

2	menny	2

3	linda	3

4	shory	4

5	xuying	5

6	xujun	6

7	taoju	7

8	beibei	8

select c1, c2, rownum from t1 where 5 >= rownum ;

c1	c2	rownum

1	jim	1

2	menny	2

3	linda	3

4	shory	4

5	xuying	5

select c1, c2, rownum from t1 where rownum != 1;

c1	c2	rownum

select c1, c2, rownum from t1 where rownum < 1;

c1	c2	rownum

select c1, c2, rownum from t1 where rownum < 5;

c1	c2	rownum

1	jim	1

2	menny	2

3	linda	3

4	shory	4

###############################################

"test rownum when join and subquery"

select * from (select rownum row_id, c1, c2 from t1) where row_id < 3 and row_id >5;

row_id	c1	c2

select * from (select rownum row_id, c1, c2 from t1) where row_id > 1 and row_id <5;

row_id	c1	c2

2	2	menny

3	3	linda

4	4	shory

select * from (select rownum row_id, c1, c2 from t1) where row_id < 3 or row_id > 5;

row_id	c1	c2

1	1	jim

2	2	menny

6	6	xujun

7	7	taoju

8	8	beibei

select * from (select rownum row_id, c1, c2, c4 from t1) where row_id < 7 and c4=1;

row_id	c1	c2	c4

1	1	jim	1

2	2	menny	1

3	3	linda	1

5	5	xuying	1

select * from (select tmp_page.*, rownum row_id from (select d.c1 as c1, d.c2 as c2, to_char(d.c3, 'YYYY-MM-DD HH:MI:SS') as xxtime, so.c3 as status from t1 d left join t2 so on d.c1=so.c1 and so.c4=1 where 1=1 and d.c4=1 order by d.c4) tmp_page where rownum <=1) where row_id > 1;

c1	c2	xxtime	status	row_id

select * from (select tmp_page.*, rownum row_id from (select d.c1 as c1, d.c2 as c2, to_char(d.c3, 'YYYY-MM-DD HH:MI:SS') as xxtime, so.c3 as status from t1 d left join t2 so on d.c1=so.c1 and so.c4=1 where 1=1 and d.c4=1 order by d.c3) tmp_page where rownum <=4) where row_id > 1;

c1	c2	xxtime	status	row_id

8	beibei	x	NULL	2

1	jim	x	2	3

1	jim	x	1	4

select * from (select tmp_page.*, rownum row_id from (select d.c1 as c1, d.c2 as c2, to_char(d.c3, 'YYYY-MM-DD HH:MI:SS') as xxtime, so.c3 as status from t1 d left join t2 so on d.c1=so.c1 and so.c4=1 where 1=1 and d.c4=1 order by d.c3) tmp_page where rownum <=4) where row_id <= 3;

c1	c2	xxtime	status	row_id

7	taoju	x	NULL	1

8	beibei	x	NULL	2

1	jim	x	2	3

select * from (select tmp_page.*, rownum row_id from (select d.c1 as c1, d.c2 as c2, to_char(d.c3, 'YYYY-MM-DD HH:MI:SS') as xxtime, so.c3 as status from t1 d left join t2 so on d.c1=so.c1 and so.c4=1 where 1=1 and d.c4=1 order by d.c3) tmp_page where rownum <=19) where row_id >=1;

c1	c2	xxtime	status	row_id

7	taoju	x	NULL	1

8	beibei	x	NULL	2

1	jim	x	2	3

1	jim	x	1	4

5	xuying	x	NULL	5

2	menny	x	2	6

2	menny	x	2	7

2	menny	x	2	8

3	linda	x	3	9

3	linda	x	4	10

###############################################

"test for update/delete"

update t2 set c3 = rownum;

select c1,c3 from t2;

c1	c3

1	1

1	2

1	3

2	4

2	5

2	6

2	7

3	8

3	9

4	10

4	11

5	12

5	13

7	14

delete from t2 where c3=rownum;

select c1,c3 from t2;

c1	c3

drop table t1;

drop table t2;

drop database test_db1;

###############################################

"test for many field in a table storge in hash"

create table tx(c1 int, c2 int, c3 int, c4 int, c5 int, c6 int, c7 int, c8 int, c9 int, c11 int, c12 int, c13 int, c14 int, c15 int, c16 int, c17 int, c18 int, c19 int,c21 int, c22 int, c23 int, c24 int, c25 int, c26 int, c27 int, c28 int, c29 int,c31 int, c32 int, c33 int, c34 int, c35 int, c36 int, c37 int, c38 int, c39 int,c41 int, c42 int, c43 int, c44 int, c45 int, c46 int, c47 int, c48 int, c49 int);

insert into tx (c1, c2) values (1,2);

insert into tx (c1, c2) values (2,2);

insert into tx (c1, c2) values (3,2);

select c1, rownum from tx;

c1	rownum

1	1

2	2

3	3

select c1, rownum from tx where rownum = 1;

c1	rownum

1	1

select c1, rownum from tx where rownum < 1;

c1	rownum

drop table tx;

woqutech added a comment - 2020-11-03 11:43 - edited The most common usage of rownum (paste from rownum.result) is: SET SQL_MODE= 'oracle' ; set optimizer_switch= 'condition_pushdown_for_derived=off,derived_merge=off' ; create database test_db1; create table t1(c1 int , c2 varchar2(20), c3 timestamp (6), c4 varchar2(2)); create table t2(c1 int , c2 char (20), c3 int , c4 varchar2(2)); insert into t1 values (1, 'jim' , '1984-08-21 18:00:00' , '1' ); insert into t1 values (2, 'menny' , '1986-10-02 20:20:00' , '1' ); insert into t1 values (3, 'linda' , '1986-11-02 20:00:00' , '1' ); insert into t1 values (4, 'shory' , '1986-10-01 00:20:00' , '0' ); insert into t1 values (5, 'xuying' , '1986-10-02 10:00:00' , '1' ); insert into t1 values (6, 'xujun' , '1988-10-02 00:00:00' , '0' ); insert into t1 values (7, 'taoju' , '1981-10-02 11:20:00' , '1' ); insert into t1 values (8, 'beibei' , '1981-11-02 00:00:00' , '1' ); insert into t2 values (1, 'jim' , 3, '0' ); insert into t2 values (1, 'jim' , 2, '1' ); insert into t2 values (1, 'jim' , 1, '1' ); insert into t2 values (2, 'menny' , 2, '1' ); insert into t2 values (2, 'menny' , 2, '1' ); insert into t2 values (2, 'menny' , 2, '1' ); insert into t2 values (2, 'menny' , 3, '0' ); insert into t2 values (3, 'linda' , 3, '1' ); insert into t2 values (3, 'linda' , 4, '1' ); insert into t2 values (4, 'shory' , 2, '1' ); insert into t2 values (4, 'shory' , 3, '0' ); insert into t2 values (5, 'xuying' , 1, '0' ); insert into t2 values (5, 'xuying' , 1, '0' ); insert into t2 values (7, 'taoju' , 3, '0' ); select * from t1; c1 c2 c3 c4 1 jim x.000000 1 2 menny x.000000 1 3 linda x.000000 1 4 shory x.000000 0 5 xuying x.000000 1 6 xujun x.000000 0 7 taoju x.000000 1 8 beibei x.000000 1 select * from t2; c1 c2 c3 c4 1 jim 3 0 1 jim 2 1 1 jim 1 1 2 menny 2 1 2 menny 2 1 2 menny 2 1 2 menny 3 0 3 linda 3 1 3 linda 4 1 4 shory 2 1 4 shory 3 0 5 xuying 1 0 5 xuying 1 0 7 taoju 3 0 ############################################### "common test for rownum" select c1, c2, rownum from t1; c1 c2 rownum 1 jim 1 2 menny 2 3 linda 3 4 shory 4 5 xuying 5 6 xujun 6 7 taoju 7 8 beibei 8 select c1, c2, rownum from t1 where rownum = 1; c1 c2 rownum 1 jim 1 select c1, c2, rownum from t1 where rownum >= 1; c1 c2 rownum 1 jim 1 2 menny 2 3 linda 3 4 shory 4 5 xuying 5 6 xujun 6 7 taoju 7 8 beibei 8 select c1, c2, rownum from t1 where 5 >= rownum ; c1 c2 rownum 1 jim 1 2 menny 2 3 linda 3 4 shory 4 5 xuying 5 select c1, c2, rownum from t1 where rownum != 1; c1 c2 rownum select c1, c2, rownum from t1 where rownum < 1; c1 c2 rownum select c1, c2, rownum from t1 where rownum < 5; c1 c2 rownum 1 jim 1 2 menny 2 3 linda 3 4 shory 4 ############################################### "test rownum when join and subquery" select * from ( select rownum row_id, c1, c2 from t1) where row_id < 3 and row_id >5; row_id c1 c2 select * from ( select rownum row_id, c1, c2 from t1) where row_id > 1 and row_id <5; row_id c1 c2 2 2 menny 3 3 linda 4 4 shory select * from ( select rownum row_id, c1, c2 from t1) where row_id < 3 or row_id > 5; row_id c1 c2 1 1 jim 2 2 menny 6 6 xujun 7 7 taoju 8 8 beibei select * from ( select rownum row_id, c1, c2, c4 from t1) where row_id < 7 and c4=1; row_id c1 c2 c4 1 1 jim 1 2 2 menny 1 3 3 linda 1 5 5 xuying 1 select * from ( select tmp_page.*, rownum row_id from ( select d.c1 as c1, d.c2 as c2, to_char(d.c3, 'YYYY-MM-DD HH:MI:SS' ) as xxtime, so.c3 as status from t1 d left join t2 so on d.c1=so.c1 and so.c4=1 where 1=1 and d.c4=1 order by d.c4) tmp_page where rownum <=1) where row_id > 1; c1 c2 xxtime status row_id select * from ( select tmp_page.*, rownum row_id from ( select d.c1 as c1, d.c2 as c2, to_char(d.c3, 'YYYY-MM-DD HH:MI:SS' ) as xxtime, so.c3 as status from t1 d left join t2 so on d.c1=so.c1 and so.c4=1 where 1=1 and d.c4=1 order by d.c3) tmp_page where rownum <=4) where row_id > 1; c1 c2 xxtime status row_id 8 beibei x NULL 2 1 jim x 2 3 1 jim x 1 4 select * from ( select tmp_page.*, rownum row_id from ( select d.c1 as c1, d.c2 as c2, to_char(d.c3, 'YYYY-MM-DD HH:MI:SS' ) as xxtime, so.c3 as status from t1 d left join t2 so on d.c1=so.c1 and so.c4=1 where 1=1 and d.c4=1 order by d.c3) tmp_page where rownum <=4) where row_id <= 3; c1 c2 xxtime status row_id 7 taoju x NULL 1 8 beibei x NULL 2 1 jim x 2 3 select * from ( select tmp_page.*, rownum row_id from ( select d.c1 as c1, d.c2 as c2, to_char(d.c3, 'YYYY-MM-DD HH:MI:SS' ) as xxtime, so.c3 as status from t1 d left join t2 so on d.c1=so.c1 and so.c4=1 where 1=1 and d.c4=1 order by d.c3) tmp_page where rownum <=19) where row_id >=1; c1 c2 xxtime status row_id 7 taoju x NULL 1 8 beibei x NULL 2 1 jim x 2 3 1 jim x 1 4 5 xuying x NULL 5 2 menny x 2 6 2 menny x 2 7 2 menny x 2 8 3 linda x 3 9 3 linda x 4 10 ############################################### "test for update/delete" update t2 set c3 = rownum; select c1,c3 from t2; c1 c3 1 1 1 2 1 3 2 4 2 5 2 6 2 7 3 8 3 9 4 10 4 11 5 12 5 13 7 14 delete from t2 where c3=rownum; select c1,c3 from t2; c1 c3 drop table t1; drop table t2; drop database test_db1; ############################################### "test for many field in a table storge in hash" create table tx(c1 int , c2 int , c3 int , c4 int , c5 int , c6 int , c7 int , c8 int , c9 int , c11 int , c12 int , c13 int , c14 int , c15 int , c16 int , c17 int , c18 int , c19 int ,c21 int , c22 int , c23 int , c24 int , c25 int , c26 int , c27 int , c28 int , c29 int ,c31 int , c32 int , c33 int , c34 int , c35 int , c36 int , c37 int , c38 int , c39 int ,c41 int , c42 int , c43 int , c44 int , c45 int , c46 int , c47 int , c48 int , c49 int ); insert into tx (c1, c2) values (1,2); insert into tx (c1, c2) values (2,2); insert into tx (c1, c2) values (3,2); select c1, rownum from tx; c1 rownum 1 1 2 2 3 3 select c1, rownum from tx where rownum = 1; c1 rownum 1 1 select c1, rownum from tx where rownum < 1; c1 rownum drop table tx;

Michael Widenius added a comment - 2020-11-17 13:15

I will send you the patch to review

Michael Widenius added a comment - 2020-11-17 13:15 I will send you the patch to review

MariaDB Server

support oracle syntax: rownum

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