mySQL union with calculated row - mysql

I have a query similar to this:
select 'table_1', count(*)
from table_1
union
select 'table_2', count(*)
from table_2
union
select 'table_n', count(*)
from table_n
returning the total of rows for each table (n tables).
table_1 | 100
table_2 | 150
table_n | 400
I want to know if there is a mysql function that can just add a new record at the end making the sum of all rows like this:
table_1 | 100
table_2 | 150
table_n | 400
total | 650
Is there a way to do that in mySQL (version 5.5) whithout using a procedure?
(for exemple using a variable inside the sql if supported)


select ifnull(table_name,'Total'), sum(row_count)
from (select 'table_1' table_name, count(*) row_count
from table_1
union
select 'table_2' table_name, count(*) row_count
from table_2
union
select 'table_n' table_name, count(*) row_count
from table_n ) temp
group by table_name with rollup;


Maybe use WITH ROLLUP:-
SELECT TableName, TableCount
FROM
(
SELECT 'table_1' AS TableName, COUNT(*) AS TableCount
FROM table_1
union
SELECT 'table_2' AS TableName, COUNT(*) AS TableCount
FROM table_2
SELECT
select 'table_n' AS TableName, COUNT(*) AS TableCount
FROM table_n
) Sub1
GROUP BY TableName, TableCount WITH ROLLUP


If you are only after the the number of rows, you should use the system table.
This will have the advantage that if you are preparing the query you don't have to hard code the table names as these can be passed as parameters:
select ifnull(table_name,'Total') as table_name, sum(table_rows) as table_rows
from (
SELECT
TABLE_NAME,
TABLE_ROWS
FROM
INFORMATION_SCHEMA.TABLES
WHERE
TABLE_NAME IN ('tOne', 'tTwo', 'tThree')
) temp
group by table_name with rollup;


select 'table_1', count(*)
from table_1
union
select 'table_2', count(*)
from table_2
union
select 'table_n', count(*)
from table_n
union
select 'total', sum(a.count)
from (
select 'table_1', count(*)
from table_1
union
select 'table_2', count(*)
from table_2
union
select 'table_n', count(*)
from table_n
) a

Related

SQL merge different table data counts

Below is my query to get some data for dashboard screen.
SELECT COUNT(*) as occupied_rooms FROM rooms where available='N' ;
SELECT COUNT(*) as checkedIn_guests FROM booking where checkout_time='' ;
SELECT COUNT(*) as available_rooms FROM rooms where available='Y' ;
SELECT COUNT(*) as total_guest FROM booking;
SELECT COUNT(*) as total_booking FROM booking;
SELECT COUNT(*) as total_staff FROM employee;
It produce output as show in above
How ever I want the output like given above image.

Use union all
SELECT 'occupied_rooms' as which, COUNT(*) as cnt FROM rooms where available = 'N'
UNION ALL
SELECT 'checkedIn_guests', COUNT(*) FROM booking where checkout_time = ''
UNION ALL
SELECT 'available_rooms', COUNT(*) FROM rooms where available = 'Y' ;
UNION ALL
SELECT 'total_guest', COUNT(*) FROM booking;
UNION ALL
SELECT 'total_booking', COUNT(*) FROM booking;
UNION ALL
SELECT 'total_staff', COUNT(*) FROM employee;
You could make the query a bit more efficient by combining the queries that reference the same table. But the overall structure would be essentially the same.

You could use a UNION for build single table result with each result in a row
SELECT 'occupied_rooms', COUNT(*) count
FROM rooms
where available='N'
UNION
SELECT 'checkedIn_guests', COUNT(*)
FROM booking
where checkout_time=''
UNION
SELECT 'available_rooms', COUNT(*)
FROM rooms
where available='Y'
UNION
SELECT 'total_guest', COUNT(*)
FROM booking
UNION
SELECT 'total_booking', COUNT(*)
FROM booking
UNION
SELECT 'total_staff', COUNT(*)
FROM employee;

Check which IDs from a set do not exists in a table

I have a list of user IDs, like this:
757392,733602,749955,744304,746852,753904,755117,636163,564931,740787,751450,743799,643918,
749903,571888,30207,705953,749120,749001,749192,749978,750840,544228,702121,746246,383667,
558790,585628,592771,745818,749375,241209,749235,746860,748318,748016,748951,747321,748684,
748225,565375,748673,747869,748522,748335,744775,672229,578056,713127,740234,632608,711135,
746528,362131,742223,746567,745224,332989,439837,745418,673582,269584,742606,745135,746950,
476134,740830,742949,276934
I have a MySQL table users with the id field.
How do I check - using a query - which IDs of the ones I have do not exists in the users table?
This sounds like a simple problem to me, yet I couldn't find any example on StackOverflow which would address a fixed set of ID values.

I didn't know the find_in_set() function and took a more handcrafted approach. Not that it makes any sense given the first answer, but I'll post it anyway:
SELECT id
FROM (
SELECT '757392' AS id UNION
SELECT '733602' UNION
SELECT '749955' UNION
SELECT '744304' UNION
SELECT '746852' UNION
SELECT '753904' UNION
SELECT '755117' UNION
SELECT '636163' UNION
SELECT '564931' UNION
SELECT '740787' UNION
SELECT '751450' UNION
SELECT '743799' UNION
SELECT '643918' UNION
SELECT '749903' UNION
SELECT '571888' UNION
SELECT '30207' UNION
SELECT '705953' UNION
SELECT '749120' UNION
SELECT '749001' UNION
SELECT '749192' UNION
SELECT '749978' UNION
SELECT '750840' UNION
SELECT '544228' UNION
SELECT '702121' UNION
SELECT '746246' UNION
SELECT '383667' UNION
SELECT '558790' UNION
SELECT '585628' UNION
SELECT '592771' UNION
SELECT '745818' UNION
SELECT '749375' UNION
SELECT '241209' UNION
SELECT '749235' UNION
SELECT '746860' UNION
SELECT '748318' UNION
SELECT '748016' UNION
SELECT '748951' UNION
SELECT '747321' UNION
SELECT '748684' UNION
SELECT '748225' UNION
SELECT '565375' UNION
SELECT '748673' UNION
SELECT '747869' UNION
SELECT '748522' UNION
SELECT '748335' UNION
SELECT '744775' UNION
SELECT '672229' UNION
SELECT '578056' UNION
SELECT '713127' UNION
SELECT '740234' UNION
SELECT '632608' UNION
SELECT '711135' UNION
SELECT '746528' UNION
SELECT '362131' UNION
SELECT '742223' UNION
SELECT '746567' UNION
SELECT '745224' UNION
SELECT '332989' UNION
SELECT '439837' UNION
SELECT '745418' UNION
SELECT '673582' UNION
SELECT '269584' UNION
SELECT '742606' UNION
SELECT '745135' UNION
SELECT '746950' UNION
SELECT '476134' UNION
SELECT '740830' UNION
SELECT '742949' UNION
SELECT '276934') AS id_list
WHERE id NOT IN (
SELECT id
FROM users);

This is an option:
SELECT ids.id
FROM ( SELECT #i
, substring(#string, #start, #end-#start) id
FROM <BigTable>
, ( SELECT #string := <YourStringOfIds>
, #start:=0
, #end:=0
, #i:=0
, #len:=length(#string)
, #n:=#len-length(replace(#string,',',''))+1
) t
WHERE (#i := #i+1) <= #n
AND (#start := #end+1)
AND (#loc := locate(',',#string,#start))
AND #end := if(#loc!=0,#loc,#len+1)
) ids
LEFT JOIN <BigTable> u
ON u.id = ids.id
WHERE u.id is null
BigTable can be any table whose number of rows >= number of ids in your string.

Create temporary table, then fill it
CREATE TABLE tmp (
`id` INT NOT NULL,
PRIMARY KEY (`id`));
INSERT INTO tmp (id) VALUES (1),(2),(3),(4),(5),(6)
then make a query
SELECT tmp.id
FROM tmp
LEFT JOIN users u ON u.id = tmp.id
WHERE tmp.id IS NULL
finally drop the table
DROP TABLE tmp

You're looking for the IN clause with a negation. I.e. you can specify your list as the argument to the IN clause like so:
SELECT * FROM users
WHERE id NOT IN ( 757392,733602,749955,744304,746852,753904,755117,636163,564931,740787,751450,743799,643918,749903,571888,30207,705953,749120,749001,749192,749978,750840,544228,702121,746246,383667,558790,585628,592771,745818,749375,241209,749235,746860,748318,748016,748951,747321,748684,748225,565375,748673,747869,748522,748335,744775,672229,578056,713127,740234,632608,711135,746528,362131,742223,746567,745224,332989,439837,745418,673582,269584,742606,745135,746950,476134,740830,742949,276934 );
UPDATE
My bad - I didn't read the question properly.
So the correct way would be to go with UNIONs then outer join and filter by NULL, like this:
SELECT WantedIds.id
FROM users
RIGHT JOIN (
SELECT x.id
FROM (
SELECT '757392' AS id UNION
SELECT '733602' UNION
SELECT '749955' UNION
SELECT '744304' UNION
SELECT '746852' UNION
SELECT '753904' UNION
SELECT '755117' UNION
SELECT '636163' UNION
SELECT '564931' UNION
.
.
.
) x
) WantedIds
ON WantedIds.id = users.id
WHERE users.id IS NULL

You can use MySQL's find_in_set() function to check if a value exists in a commase separated list of values:
select * from your_table
where find_in_set(field_name,'757392,733602,749955,744304,746852,753904,755117,636163,564931,740787,751450')=0

MYSQL total count more than 1 table total result

I have 3 tables. I want to select count in 1 result, like:
table1=1000 records + table2=400 records + table3=200 records = 1600
1600 is the one result I want back from the server.
MySQL inner join perhaps? Any suggestions?

Try this :
select sum(c) from (
select count(*) as c from table1
union
select count(*) as c from table2
union
select count(*) as c from table3
) tmp
That'll give you the total.

select
(
select count(columnname) from table1
) + (
select count(columnname) from table2
)+ (
select count(columnname) from table3
)

try this...,
SELECT (SELECT COUNT(*) FROM tbl1
)+
(SELECT COUNT(*) FROM tbl2
)+
( SELECT COUNT(*) FROM tbl3
) as 'AllCount'

select
((select count(*) from table1) + (select count(*) from table2) + (select count(*) from table3))
as totalCount;

Try this:
SELECT ((SELECT COUNT(*) FROM tbl1 ) + (SELECT COUNT(*) FROM tbl2 ) + (SELECT COUNT(*) FROM tbl3 )) AS TotalRecords

Thank you all for your responses I have 3 tables and i want to select a count in 1 single result
still i get results back like this
count1 count2 count3
1235 134 234
and this is not what i want a total one result

MySQL; Get information from 3 table same time

People
here is my little problem.
I have three table:
a_names_1
b_names_2
c_names_3
they are same by structure. all of them has two item: name and used
Is there any QUERY to run to get and count all the 'name' that has 'used'=1 from all those three tables together.
I've tried this one, but didn't work:
(SELECT COUNT(*) 'name' from a_names_1) UNION
(SELECT COUNT(*) 'name' from a_names_2) UNION
(SELECT COUNT(*) 'name' from a_names_3) WHERE `used`=1
I'm using PHPMyAdmin for MySQL.
Any Help would be appreciated.. thanks in advance

This query outputs count of distinct names from all tables with used=1
select count(distinct name)
from
(
select name,used from a_names_1 where used=1
union all
select name,used from a_names_2 where used=1
union all
select name,used from a_names_3 where used=1
) t
If you need to SUM all USED for each NAME from all tables and output only with SUM of used=1 then:
select count(*) from
(
select name, SUM(used)
from
(
select name,used from a_names_1
union all
select name,used from a_names_2
union all
select name,used from a_names_3
) t
GROUP BY name
HAVING SUM(used)=1
) t1

select count(*) as name
from
(
select name, used from a_names_1
union
select name, used from a_names_2
union
select name, used from a_names_3) t
where t.used = 1

Probably this is slow, because you lose the index optimizations. What I would do is do the three queries, something like
SELECT SUM('name') AS name_sum
FROM ((SELECT COUNT(*) 'name' from a_names_1 WHERE `used`=1)
UNION (SELECT COUNT(*) 'name' from a_names_2 WHERE `used`=1));
If this doesn't work, it is probably a problem with the usage of name

Maybe you wanted this way:
select count(*) as cnt
from
(
select name from a_names_1 t1 where t1.used = 1
union
select name from a_names_2 t2 where t2.used = 1
union
select name from a_names_3 t3 where t3.used = 1
) t

The straight forward solution;
SELECT SUM(used) FROM (
SELECT used FROM a_names_1 WHERE used=1
UNION ALL
SELECT used FROM a_names_2 WHERE used=1
UNION ALL
SELECT used FROM a_names_3 WHERE used=1
) a
SQLfiddle for testing
An alternative if you have an index on used (and the only values of used are 0 or 1) is to just do the counting using the index;
SELECT SUM(used) total FROM (
SELECT SUM(used) used FROM a_names_1
UNION ALL
SELECT SUM(used) FROM a_names_2
UNION ALL
SELECT SUM(used) FROM a_names_3
) a
SQLfiddle for this example.
If you look at the query plan of the latter query, you can see it uses the indexes effectively.

How to calculate Sum of Count(*) in Mysql

I have two tables that I count rows of them. For example;
Select count(*) FROM tbl_Events
Select count(*) FROM tbl_Events2
I need total count. How can I sum the result with a single statement?

select sum(cnt) from (
select count(*) as cnt from tbl_events
union all
select count(*) as cnt from tbl_events2
) as x

Try this:
SELECT (Select count(*) FROM tbl_Events) + (Select count(*) FROM tbl_Events2)
Or (tested in MSSQL), this:
SELECT COUNT(*)
FROM (SELECT * FROM tbl_Events
UNION ALL
SELECT * FROM tbl_Events2) AS AllEvents
I'd guess the first will lead to better performance because it has more obvious index options. Test to be sure, though.

Select Count(*)
From(
Select * From tbl_Events
Union All
Select * From tbl_Events2) as A