in my database I have 3 tables named items, manufacturers and items_manufacturers. manufacturers has a HAS:MANY relation with items_manufacturers
My items table
+---------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------+--------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| code | varchar(25) | NO | MUL | NULL | |
| item_category | varchar(100) | NO | | NULL | |
| item_desc | varchar(500) | NO | | NULL | |
| reorder_point | int(11) | NO | | NULL | |
| unit | varchar(45) | NO | | NULL | |
+---------------+--------------+------+-----+---------+----------------+
My manufacturers table
+------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| code | varchar(25) | NO | | NULL | |
| name | varchar(250) | NO | | NULL | |
| address | varchar(750) | NO | | NULL | |
| contact_no | varchar(50) | NO | | NULL | |
+------------+--------------+------+-----+---------+----------------+
My items_manufacturers table
+-----------------+---------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------+---------------+------+-----+---------+----------------+
| id | bigint(20) | NO | PRI | NULL | auto_increment |
| item_id | bigint(20) | NO | MUL | NULL | |
| manufacturer_id | bigint(20) | NO | MUL | NULL | |
| unit_cost | decimal(20,2) | NO | | NULL | |
| vendor_id | bigint(20) | NO | | NULL | |
+-----------------+---------------+------+-----+---------+----------------+
In my result table I want items_id, items_desc, name of manufacturer from manufacturers table and manufacturer_id. The relation I have is
items.id=items_manufacturers.item_id and
manufacturers.id=items_manufacturers.manufacturer_id.
I tried using inner joins for three tables but not working.
The query I tried
select
items_manufacturers.id,
items.item_desc,
item_manufacturers.manufacturer_id,
manufacturer.name
from items_manufacturers
INNER JOIN items ON items_manufacturers.item_id=items.id
INNER JOIN manufacturers ON items_manufacturers.manufacturer_id=manufacturers.id
Anybody kindly help me with this, I am stuck up from a long time
I used this following code and got the result you were trying to get. This code may solve your problem:
select a.name,b.manufacturer_id,c.id,c.item_desc
from manufacturers as a
inner join
item_manufacturers as b
on b.manufacturer_id=a.id
inner join item as c
on c.id=b.item_id
Related
I have the following 2 tables (student and attendance):
mysql> describe student;
+----------------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------------------+--------------+------+-----+---------+----------------+
| student_id | int(11) | NO | PRI | NULL | auto_increment |
| student_email | varchar(255) | YES | | NULL | |
| student_phone_number | varchar(255) | YES | | NULL | |
| parent_first_name | varchar(255) | NO | | NULL | |
| parent_last_name | varchar(255) | NO | | NULL | |
| parent_email | varchar(255) | NO | | NULL | |
| parent_phone_number | varchar(255) | NO | | NULL | |
| first_name | varchar(255) | NO | | NULL | |
| last_name | varchar(255) | NO | | NULL | |
| days_absent | int(11) | YES | | NULL | |
| days_tardy | int(11) | YES | | NULL | |
| class_id | int(11) | NO | MUL | NULL | |
+----------------------+--------------+------+-----+---------+----------------+
mysql> describe attendance;
+-----------------+------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------------+------------+------+-----+---------+-------+
| student_id | int(11) | NO | PRI | NULL | |
| class_id | int(11) | NO | PRI | NULL | |
| attendance_date | date | NO | PRI | NULL | |
| absent | tinyint(1) | YES | | NULL | |
| tardy | tinyint(1) | YES | | NULL | |
| note | text | YES | | NULL | |
+-----------------+------------+------+-----+---------+-------+
I want to check the attendance and email of all the children who are absent or tardy for the day. Is there a SQL statement I can use that can, for example, select the students from attendance with an absent/tardy value = 1, then using that student_id specified in the attendance table, pull all the student info from the student table where attendance.student_id = student.student_id?
just try exists
select student_email,student_phone_number from student std
where exists(
select 1 from attendance atd where std.student_id = atd.student_id
and (atd.absent =1 or atd.tardy =1)
)
just make sure you select all the info from student table and exists all the filter in attendance talbe. the condition is student_id.
Also if you need info from attendance talbe, then use join.
Im trying to make a mysql join statement. I want to join the idRestauraunt of Restauraunts and the idRestauraunt of restaurant_categories. My second join i want to join idCategories of Categories and idCategory of restaurant_categories. The query that I'm trying to use is
SELECT distinct r.* from Restaurants r
JOIN restaurant_categories rc on(r.idRestaurant = rc.idRestaurant )
JOIN Categories c on (c.idCategories =rc.idCategories )
WHERE c.Category ='Pizza Hut'
Error Code: 1066. Not unique table/alias: 'Restaurants'
Categories
+--------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+-------------+------+-----+---------+-------+
| idCategories | int(11) | NO | PRI | NULL | |
| Category | varchar(45) | YES | | NULL | |
+--------------+-------------+------+-----+---------+-------+
Restaurants
+--------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+-------------+------+-----+---------+-------+
| idRestaurant | int(11) | NO | PRI | NULL | |
| Name | varchar(45) | YES | | NULL | |
| Password | varchar(45) | YES | | NULL | |
| Email | varchar(45) | YES | | NULL | |
| Number | varchar(45) | YES | | NULL | |
+--------------+-------------+------+-----+---------+-------+
restaurant_categories
+--------------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+---------+------+-----+---------+-------+
| idCategory | int(11) | YES | MUL | NULL | |
| idRestaurant | int(11) | YES | MUL | NULL | |
+--------------+---------+------+-----+---------+-------+
My database structure contains:
actions
+--------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| placement_id | int(11) | YES | MUL | NULL | |
| lead_id | int(11) | NO | MUL | NULL | |
+--------------+--------------+------+-----+---------+----------------+
placements
+--------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| publisher_id | int(11) | YES | MUL | NULL | |
| name | varchar(255) | NO | | NULL | |
| status | tinyint(1) | NO | | NULL | |
+--------------+--------------+------+-----+---------+----------------+
leads
+---------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------+--------------+------+-----+---------+----------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| status | varchar(255) | YES | | NULL | |
+---------+--------------+------+-----+---------+----------------+
I would like to retrieve a number of statuses per each placement (groupped):
| placement_id | placement_name | count
+--------------+----------------+-------
| 123 | PlacementOne | 12
| 567 | PlacementTwo | 15
I tried countless times and every query I wrote seems dumb, so I won't even post them here. I'm hopeless. An well commented query (so I can learn) would be much appreciated.
select a.placement_id, p.name as placement_name, count(l.status)
from actions a
inner join placements p on p.id = a.placement_id
inner join leads l on l.id = a.lead_id
group by a.placement_id, p.name
I have two tables
members
+------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+-------------+------+-----+---------+----------------+
| mindex | smallint(4) | NO | PRI | NULL | auto_increment |
| memberid | smallint(5) | YES | MUL | NULL | |
| forenames | varchar(40) | YES | | NULL | |
| surname | varchar(20) | YES | | NULL | |
| nameprefix | varchar(30) | YES | | NULL | |
| namesuffix | varchar(50) | YES | | NULL | |
| died | smallint(5) | YES | | NULL | |
| notes | text | YES | | NULL | |
+------------+-------------+------+-----+---------+----------------+
and
memberships;
+------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------+-------------+------+-----+---------+----------------+
| mshipindex | smallint(4) | NO | PRI | NULL | auto_increment |
| memberid | smallint(5) | YES | MUL | NULL | |
| msid | smallint(5) | YES | | NULL | |
| mstype | varchar(20) | YES | | NULL | |
| msyear | smallint(5) | YES | | NULL | |
| msposition | varchar(15) | YES | | NULL | |
+------------+-------------+------+-----+---------+----------------+
I want to search on memberships for a year (in memberships.msyear) and get memberships.mstype and members.surname.
I just can't get the right JOIN syntax on this.
You will use something like this:
select m.surname,
s.mstype
from members m
left join memberships s
on m.memberid = s.memberid
where s.msyear = yourYear
See SQL Fiddle with Demo
I used a LEFT JOIN to return the all members, even those who might not have a membership record. If the member does not have a record in the memberships table, then it will return null.
If you need help learning JOIN syntax, here is a great visual explanation of joins
If you just need the syntax Here it is :
Select *
from members m
inner join membership ms on (m.memberid = ms.memberid)
where memberships.msyear = 2012
Database Tables
ss_merchant
+----------------+--------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------------+--------------+------+-----+---------+----------------+
| pk_merchant_id | bigint(20) | NO | PRI | NULL | auto_increment |
| name | varchar(45) | YES | | NULL | |
| website | varchar(100) | YES | | NULL | |
+----------------+--------------+------+-----+---------+----------------+
ss_merchant_store
+----------------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------------------+-------------+------+-----+---------+----------------+
| pk_merchant_store_id | bigint(20) | NO | PRI | NULL | auto_increment |
| fk_pk_merchant_id | bigint(20) | YES | | NULL | |
| street | varchar(20) | YES | | NULL | |
| city | varchar(20) | YES | | NULL | |
| postcode | varchar(8) | YES | | NULL | |
| telephone | varchar(15) | YES | | NULL | |
| email | varchar(45) | YES | | NULL | |
+----------------------+-------------+------+-----+---------+----------------+
ss_merchant_store_rating
+-----------------------------+------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------------------------+------------+------+-----+---------+----------------+
| pk_merchant_store_rating_id | bigint(20) | NO | PRI | NULL | auto_increment |
| fk_pk_merchant_store_id | bigint(20) | NO | | NULL | |
| rating | int(1) | YES | | NULL | |
+-----------------------------+------------+------+-----+---------+----------------+
and my query:
SELECT *
FROM ss_merchant
JOIN ss_merchant_stores
ON ss_merchant.pk_merchant_id = ss_merchant_stores.fk_pk_merchant_id
JOIN ss_merchant_store_rating
ON ss_merchant_stores.pk_merchant_store_id = ss_merchant_store_rating.fk_pk_merchant_store_id
There isn't anything specifically wrong with your join but it does make the assumption that all three tables have at least one row for each merchant_id. If you want to allow for non-existant merchant_store_rating rows consider using a LEFT JOIN
If there is no matching row for the
right table in the ON or USING part in
a LEFT JOIN, a row with all columns
set to NULL is used for the right
table. You can use this fact to find
rows in a table that have no
counterpart in another table:
SELECT left_tbl.* FROM left_tbl LEFT JOIN right_tbl
ON left_tbl.id = right_tbl.id WHERE right_tbl.id IS NULL;
This example finds all rows in
left_tbl with an id value that is not
present in right_tbl (that is, all
rows in left_tbl with no corresponding
row in right_tbl). This assumes that
right_tbl.id is declared NOT NULL.