How can I use MySQL ROW_NUMBER Function in a query - mysql

I am trying to learn about the MySQL ROW_NUMBER() function and how to use it to generate a sequential number for each row in a result set.
What I tried so far:
SELECT e.*,
ROW_NUMBER()
OVER(PARTITION BY e.examid ORDER BY e.examid) AS id
from exam e
When I run this query, a series of errors were displayed:
3 errors were found during analysis.
An alias was previously found. (near "id" at position 68)
An alias was expected. (near " " at position 67)
Unexpected token. (near "id" at position 68)
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(PARTITION BY examid ORDER BY examid) as id from exam LIMIT 0, 25' at line 1
How can I go about it?

I had the same problem. This syntax works in my case:
SELECT
(ROW_NUMBER() OVER (ORDER BY id)) row_number, Field1, Field2
FROM
myTable
ORDER BY
id
Additional remark: select version() returns 10.3.20-MariaDB-log.

Change the I'd to something else because the select * statement will return an id and it will conflict with that I'd (AS id)

Related

Understanding the rational behind ORDER BY in sql

The following query works
SELECT score, DENSE_RANK() OVER(ORDER BY score DESC) AS 'rank' FROM Scores
But when I do the following below it doesn't work
SELECT score, DENSE_RANK() OVER(ORDER BY score DESC) AS 'rank' FROM Scores ORDER BY rank
RANK is a reserved keyword in MySQL 8.0, see https://dev.mysql.com/doc/refman/8.0/en/keywords.html#keywords-8-0-detailed-R
In your ORDER BY clause, the parser thinks you are using the RANK function, and it gets confused when it reaches the end and finds you have not put () after the function name RANK. The error shows what follows the point where it got confused, which is the end of the query, so what follows is ''.
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
You can fix this and use reserved keywords as identifiers by enclosing them in back-ticks:
SELECT score, DENSE_RANK() OVER(ORDER BY score DESC) AS 'rank'
FROM Scores
ORDER BY `rank`;

SubQuery and ROWNUM in MySQL : SELECT * FROM (SELECT...)

EDIT: This solved my problem:
select id_t,punctaj
from test
where punctaj in (select punctaj from test )
order by punctaj desc
limit 1;*
I have written a working Oracle SQL code but when I'm trying to convert it to MySQL I have a syntax error which I cannot solve. It looks like MySQL does not accept ROWNUM and also SELECT * FROM a subquery. What could be the solution? I need the biggest value of "PUNCTAJ" from the tests and I need to keep that "IN". Thanks!
Here is my code:
select* from (
select id_t,punctaj
from test
where punctaj in (select punctaj from test )
order by punctaj desc)
where rownum<=1
error:#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'where rownum<=1 LIMIT 0, 25' at line 6
you have written twice the where condition,
In secondd where use AND rownum<=1

Totals and Runningtotals with SQL "sum" and "over" Syntax

In my SQL table I have "country" and "we200326" columns. Column "we200326" contains only "1" or "NULL" entries.
I'm trying to get a total of all "1"s in column "we200326" and a total by country. I have written the following statement but it gives an error but I don't know what I did wrong (I'm very new at this):
SELECT country, we200326,
(SUM(we200326) OVER () AS Total)
(SUM(we200326) OVER (PARTITION BY country) AS CountryTotal)
FROM table_name
ORDER BY CountryTotal, Country;
The error I get is this:
MySQL said: Documentation
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'OVER () AS Total)
(SUM(we200326) OVER (PARTITION BY country) AS CountryTotal)
' at line 2
I have searched for similar errors and found several (each time was a simple syntax error like a space or comma or so) I tried several versions but could not resolve my problem when following those instructions. Any help would be appreciated.
Window functions are available in MySQL 8.0 only.
In earlier versions, one option is to use subqueries:
select
country,
wewe200326,
(select sum(we200326) from table_name) total,
(select sum(we200326) from table_name t1 where t1.country = t.country) country_total
from table_name t
order by country_total, country

MySQL throwing error 1064, doesn't seem to recognize OVER command

My query is:
SELECT *,
ROW_NUMBER() OVER (ORDER BY score ASC)
FROM submissions
The error message I receive is:
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(ORDER BY score ASC) FROM submissions LIMIT 0, 25' at line 2
I am running this query in phpMyAdmin. I notice that OVER is not colored blue, nor does is it suggested as I type, unlike other command words (ORDER, ASC, etc).
This simpler query runs just fine:
SELECT * FROM submissions
I've tried putting things in quotes, using the RANK function instead, and fiddling with whitespace, but the query still doesn't run. What is wrong here?
My guess is that you are running a version of MySQL which is earlier than 8+, one which does not support ROW_NUMBER. There are a few options for simulating ROW_NUMBER in earlier versions of MySQL. One is to use user variables:
SELECT *,
(#row_number:=#row_number + 1) AS rn
FROM submissions, (SELECT #row_number := 0) tmp
ORDER BY score;

sql query order by multiple CAST value int

i'm trying to run this in sql query, but not working. I tried single cast, it works fine, but when i tried to add two cast, it gives error
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FROM useradvert WHERE optionsalerent='For sale' ORDER BY cast (rm as signed)' at line 1
This query below works.
SELECT * FROM popol WHERE optsale='For sale' ORDER BY cast(rm as signed) ASC
THis one doesn't work
SELECT * FROM popol WHERE optsale='For sale' ORDER BY cast(rm as signed) ASC, cast(salary as signed) ASC
I need to output both rm and salary rm. Both are integer values. Tqs in advance.