I want to perform a query like to get the last record of any type in DB, at my localhost, I use Maria Db and the query is as follow:
SELECT *
FROM table_a
WHERE column_a=999
OR column_b=999
GROUP
BY `group`;
group is a column which I save type in it, for instance: marketing, blog, order, etc
This query works fine on local, but on the server I get the following error:
SQLSTATE[42000]:
Syntax error or access violation:
1055 Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column
'db_name.table_a.id' which is not functionally dependent on columns in GROUP BY clause;
this is incompatible with sql_mode=only_full_group_by\n
The SQL being executed was:
SELECT * FROM `table_a` WHERE (`column_a`=999) OR (`column_b`=999) GROUP BY `group`"
According to MySQL document I can use the following command to make this possible:
SET GLOBAL sql_mode=(SELECT REPLACE(##sql_mode,'ONLY_FULL_GROUP_BY',''));
But I don't have the sufficient privilege on Db and get the following error:
#1227 - Access denied; you need (at least one of) the SUPER privilege(s) for this operation
I asked the hosting to do this for me, they replied that they don't want to do this action
I use the YII2 framework, and now I want a way to add this on the option of database_config.php of the framework or change the query to something else with the same result, and not losing performance
ONLY_FULL_GROUP_BY is a good thing, which enforces basic ANSI SQL rules. Don't change it, fix your code instead.
From there one: you want entire records, so you should not think aggregation, but filtering.
Then: in a database table, records are unordered; for your question to just make sense, you need a column that defines the ordering of rows in each group, so it unambiguous what "last" record mean. Let me assume that you have such column, called id.
Here is a typical approach at this top-1-per-group problem, using a correlated subquery for filtering:
SELECT *
FROM table_a a
WHERE
999 IN (column_a, column_b)
AND id = (
SELECT MAX(a1.id)
FROM table_a a1
WHERE 999 IN (a1.column_a, a1.column_b) AND a1.grp = a.grp
)
Alternatively, if you are running MySQL 8.0, you can use window functions:
SELECT *
FROM (
SELECT a.*,
ROW_NUMBER() OVER(PARTITION BY grp ORDER BY id DESC) rn
FROM table_a a
WHERE 999 IN (column_a, column_b)
) a
WHERE rn = 1
Side note: group is a language keyword, hence a poor choice for a column name. I renamed it to grp in the queries.
There are a few ways to "bypass" the sql_mode but be aware that the result you get might not be correct.
First you can use ANY_VALUE(). Example like this:
SELECT any_value(column_a), any_value(column_b), `group` FROM table_a
WHERE (column_a=999) OR (column_b=999) GROUP BY `group`;
When using ANY_VALUE() function you have to write all the columns in SELECT from the table and append with ANY_VALUE() except for the column that you use in the GROUP BY.
Using MAX() or MIN() can return result but still it might not be the correct
result, especially for any row(s) that have more than 1 count:
SELECT MAX(column_a), MAX(column_b), `group`
FROM table_a
WHERE (column_a=999) OR (column_b=999) GROUP BY `group`;
Using GROUP_CONCAT will give you a view at what are the values in non-grouped columns. Compare the results with the other queries above and you can see on row(s) that returns more than one count, does the other queries returning according to what you want?
SELECT group_concat(column_a), group_concat(column_b), group_concat(`group`)
FROM table_a
WHERE (column_a=999) OR (column_b=999) GROUP BY `group`;
I'm not sure if you can do this but you can set the sql_mode off temporarily then you should be able to run your query:
SET sql_mode=""; -- you don't need to set global privilege.
SELECT * FROM table_a
WHERE (column_a=999) OR (column_b=999) GROUP BY `group`;
Demo here.
Still, the best option is to retain the sql_mode as it is and construct the query according to the requirement.
P/S: GROUP is a reserved word in both MySQL & MariaDB. You can use it as column name but you have to always add back-ticks to define the column or else, running the query will return you an error like
Query: select * from table_a group by group
Error Code: 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 'group' at line 1
I am wondering if there is away (possibly a better way) to order by the order of the values in an IN() clause.
The problem is that I have 2 queries, one that gets all of the IDs and the second that retrieves all the information. The first creates the order of the IDs which I want the second to order by. The IDs are put in an IN() clause in the correct order.
So it'd be something like (extremely simplified):
SELECT id FROM table1 WHERE ... ORDER BY display_order, name
SELECT name, description, ... WHERE id IN ([id's from first])
The issue is that the second query does not return the results in the same order that the IDs are put into the IN() clause.
One solution I have found is to put all of the IDs into a temp table with an auto incrementing field which is then joined into the second query.
Is there a better option?
Note: As the first query is run "by the user" and the second is run in a background process, there is no way to combine the 2 into 1 query using sub queries.
I am using MySQL, but I'm thinking it might be useful to have it noted what options there are for other DBs as well.
Use MySQL's FIELD() function:
SELECT name, description, ...
FROM ...
WHERE id IN([ids, any order])
ORDER BY FIELD(id, [ids in order])
FIELD() will return the index of the first parameter that is equal to the first parameter (other than the first parameter itself).
FIELD('a', 'a', 'b', 'c')
will return 1
FIELD('a', 'c', 'b', 'a')
will return 3
This will do exactly what you want if you paste the ids into the IN() clause and the FIELD() function in the same order.
See following how to get sorted data.
SELECT ...
FROM ...
WHERE zip IN (91709,92886,92807,...,91356)
AND user.status=1
ORDER
BY provider.package_id DESC
, FIELD(zip,91709,92886,92807,...,91356)
LIMIT 10
Two solutions that spring to mind:
order by case id when 123 then 1 when 456 then 2 else null end asc
order by instr(','||id||',',',123,456,') asc
(instr() is from Oracle; maybe you have locate() or charindex() or something like that)
If you want to do arbitrary sorting on a query using values inputted by the query in MS SQL Server 2008+, it can be done by creating a table on the fly and doing a join like so (using nomenclature from OP).
SELECT table1.name, table1.description ...
FROM (VALUES (id1,1), (id2,2), (id3,3) ...) AS orderTbl(orderKey, orderIdx)
LEFT JOIN table1 ON orderTbl.orderKey=table1.id
ORDER BY orderTbl.orderIdx
If you replace the VALUES statement with something else that does the same thing, but in ANSI SQL, then this should work on any SQL database.
Note:
The second column in the created table (orderTbl.orderIdx) is necessary when querying record sets larger than 100 or so. I originally didn't have an orderIdx column, but found that with result sets larger than 100 I had to explicitly sort by that column; in SQL Server Express 2014 anyways.
SELECT ORDER_NO, DELIVERY_ADDRESS
from IFSAPP.PURCHASE_ORDER_TAB
where ORDER_NO in ('52000077','52000079','52000167','52000297','52000204','52000409','52000126')
ORDER BY instr('52000077,52000079,52000167,52000297,52000204,52000409,52000126',ORDER_NO)
worked really great
Ans to get sorted data.
SELECT ...
FROM ...
ORDER BY FIELD(user_id,5,3,2,...,50) LIMIT 10
The IN clause describes a set of values, and sets do not have order.
Your solution with a join and then ordering on the display_order column is the most nearly correct solution; anything else is probably a DBMS-specific hack (or is doing some stuff with the OLAP functions in standard SQL). Certainly, the join is the most nearly portable solution (though generating the data with the display_order values may be problematic). Note that you may need to select the ordering columns; that used to be a requirement in standard SQL, though I believe it was relaxed as a rule a while ago (maybe as long ago as SQL-92).
Use MySQL FIND_IN_SET function:
SELECT *
FROM table_name
WHERE id IN (..,..,..,..)
ORDER BY FIND_IN_SET (coloumn_name, .., .., ..);
For Oracle, John's solution using instr() function works. Here's slightly different solution that worked -
SELECT id
FROM table1
WHERE id IN (1, 20, 45, 60)
ORDER BY instr('1, 20, 45, 60', id)
I just tried to do this is MS SQL Server where we do not have FIELD():
SELECT table1.id
...
INNER JOIN
(VALUES (10,1),(3,2),(4,3),(5,4),(7,5),(8,6),(9,7),(2,8),(6,9),(5,10)
) AS X(id,sortorder)
ON X.id = table1.id
ORDER BY X.sortorder
Note that I am allowing duplication too.
Give this a shot:
SELECT name, description, ...
WHERE id IN
(SELECT id FROM table1 WHERE...)
ORDER BY
(SELECT display_order FROM table1 WHERE...),
(SELECT name FROM table1 WHERE...)
The WHEREs will probably take a little tweaking to get the correlated subqueries working properly, but the basic principle should be sound.
My first thought was to write a single query, but you said that was not possible because one is run by the user and the other is run in the background. How are you storing the list of ids to pass from the user to the background process? Why not put them in a temporary table with a column to signify the order.
So how about this:
The user interface bit runs and inserts values into a new table you create. It would insert the id, position and some sort of job number identifier)
The job number is passed to the background process (instead of all the ids)
The background process does a select from the table in step 1 and you join in to get the other information that you require. It uses the job number in the WHERE clause and orders by the position column.
The background process, when finished, deletes from the table based on the job identifier.
I think you should manage to store your data in a way that you will simply do a join and it will be perfect, so no hacks and complicated things going on.
I have for instance a "Recently played" list of track ids, on SQLite i simply do:
SELECT * FROM recently NATURAL JOIN tracks;
I have 2 tables with similar columns in MYSQL. I am copying data from one to another with INSERT INTO table2 SELECT * FROM table1 WHERE column1=smth. I have different columns as autoincrement and KEY in tables. When I use mysqli_insert_id i get the first one rather then last one inserted. Is there any way to get the last one?
Thanks
There is no inherit ordering of data in a relational database. You have to specify which field it is that you wish to order by like:
INSERT INTO table2
SELECT *
FROM table1
WHERE column1=smth
ORDER BY <field to sort by here>
LIMIT 1;
Relying on the order a record is written to a table is a very bad idea. If you have an auto-numbered id on table1 then just use ORDER BY id DESC LIMIT 1 to sort the result set by ID in descending order and pick the last one.
Updated to address OP's question about mysqli_insert_id
According to the Mysql reference the function called here is last_insert_id() where it states:
Important If you insert multiple rows using a single INSERT statement,
LAST_INSERT_ID() returns the value generated for the first inserted
row only. The reason for this is to make it possible to reproduce
easily the same INSERT statement against some other server.
Unfortunately, you'll have to do a second query to get the true "Last inserted id". Your best bet might be to run a SELECT COUNT(*) FROM table1 WHERE column1=smth; and then use that count(*) return to add to the mysqli_insert_id value. That's not great, but if you have high volume where this one function is getting hit a lot, this is probably the safest route.
The less safe route would be SELECT max(id) FROM table2 or SELECT max(id) FROM table2 Where column1=smth. But... again, depending on your keys and the number of times this insert is getting hit, this might be risky.
Is this possible in sql :
COUNT(ads.id) AS ads, *
If not, then what to use? I'm using LEFT JOIN, there are two tables: ads and ad, but I'm not using GROUP BY:
SELECT COUNT(ads.id) AS ads_count,
ads.*
FROM ...
It's not working.
It's certainly possible to include a * in the SELECT list alongside other columns, in general. But COUNT() is an aggregate function, and the implication there is that you're grouping by every other column in the resultset, which is probably not true.
Whether or not that query will function may be heavily dependent on which DBMS you're using, which you haven't specified. In MS SQL Server, you must declare all non-aggregate columns in a GROUP BY clause, and * is not a valid member in a GROUP BY clause, hence in SQL Server that's an invalid query.
MySQL seems to have somewhat looser rules around grouping and using aggregate functions, so it's possible that query may be syntactically valid (I don't have a MySQL database handy to test it), but its results would almost certainly be indeterminate...
You could do something like this:
-- test table
declare #T table(name varchar(10), number int)
select *, count(name)
from #T
group by number, name
In MSSQL, if you select * then you would have to list all of the columns in the group by.
Of course the only counts that would be greater then 1 would be for duplicated rows.
This should work:
SELECT COUNT(ads.id) AS ads_count,
ads2.*
FROM table_name ads
JOIN table_name ads2
GROUP BY ads.id
table_name should be your table name.
Usually I would have a table field called ID on auto increment. That way I could order using this field etc.
However I have no control over the structure of a table, and wondered how to get the results in reverse order to default.
I'm currently using
$q = mysql_query("SELECT * FROM ServerChat LIMIT 15");
However like I said there is no field I can order on, so is there a way to tell mysql to reverse the order it gets the results? I.e last row to first row instead of the default.
MySQL supports ordering by ordinal column position:
SELECT * FROM ServerChat ORDER BY 1 DESC LIMIT 15
But IIRC this usage of ORDER BY is deprecated in the SQL standard. Don't be surprised if some RDBMS vendors discontinue support for it (eventually).
In general, it's better to know your table structure.
No. Without a field to order there is no way
You are in fact getting your results in what is known as "table order", which may look like it's in the order that data was added to the table but that order is not stable. There are a number of operations that can change the order you are receiving results without changing the data in the table itself.
To reproduce the sort of order you are seeing I'd suggest adding a column to your table of type ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP. This will give you a column to specifically order on and therefore reverse that order. You should probably add an index on that column as well if this operation is a frequent one.
According to this article, SQL-92 allows the user to query table structure information from a "well known" view or table called INFORMATION_SCHEMA. SQL-92 is supported by MySQL 5.0 and up.
Example/Excerpt:
SELECT table_name, column_name, is_nullable, data_type, character_maximum_length
FROM INFORMATION_SCHEMA.Columns
WHERE table_name = 'employees'
So you could use the list of column names to allow the user to select which column it's ordered by, then use this SO answer to figure out how to build the dynamic SQL so you execute the query correctly.
I've not tried it with MySQL, but the method certainly makes sense to me.
Your table must have some unique index specified. It doesn't have to be named ID but it's typically required and likely what's determining the order returned currently. What is it? Whatever it is, it's my understanding that you should be able to do an ORDER BY ... DESC (or if that doesn't work, ASC) like this example with the unique identifier hash:
$q = mysql_query("SELECT * FROM ServerChat ORDER BY `hash` DESC LIMIT 15");