So I'm not all to great at complex MySQL statements so I'm hoping you guys can help me out.
Say I have four tables, MainTable, AttrTable, NameTable, and ValueTable.
MainTable looks like this:
| id | title | category |
.........................
| 1 | First | Cat1 |
.........................
| 2 | Second| Cat2 |
.........................
| 3 | Third | Cat3 |
AttrTable looks like this:
| id | mainId | nameId | valueId |
..................................
| 1 | 1 | 1 | 2 |
..................................
| 2 | 1 | 2 | 1 |
..................................
| 3 | 2 | 1 | 3 |
..................................
| 4 | 3 | 3 | 2 |
..................................
| 1 | 3 | 1 | 1 |
NameTable and ValueTable each looks like this:
| id | title | | id | title |
.............. ..............
| 1 | foo | | 1 | bar |
.............. ..............
| 2 | john | | 2 | smith |
.............. ..............
| 3 | dink | | 3 | fink |
So I want to write a statement that combines all the data associated with each row of the MainTable into its own row. Eg: I want a statment that would give me back something like:
| 1 | First | Cat1 | foo | smith | john | bar |
| 2 | Second| Cat2 | foo | fink |
etc...
Is that possible? I'd even settle for something like:
| 1 | First | Cat1 | foo | smith |
| 1 | First | Cat1 | john | bar |
| 2 | Second | Cat2 | foo | fink |
etc...
Hopefully this all makes sense. Thanks in advance for any help.
Sounds like you just want this:
select m.id,
m.title,
m.category,
n.title,
v.title
from maintable m
left join attrtable a
on m.id = a.mainid
left join nametable n
on a.nameid = n.id
left join valuetable v
on a.valueid = v.id
see SQL Fiddle with Demo
Query not checked! (and may need to be tweaked)
select m.*, n.title, v.title from MainTable m
join AttrTable a on a.mainId = m.id
join NameTable n on n.id = a.nameId
join ValueTable v on v.id = a.valueId
Related
I have two MySQL tables (table_a and table_b) and a join table (table_c).
Table Structures:
table_a:
__________________
| table_a: |
|----------------|
| id |
| result_column |
------------------
table_b:
__________________
| table_b: |
|----------------|
| id |
| name |
------------------
table_c:
__________________
| table_c: |
|----------------|
| id |
| table_a_id |
| table_b_id |
------------------
My Goal:
I want to find a query that will:
Iterate over every table_a record and get the table_a.id value
Find any records in table_c which have a matching table_c.table_a_id value
For each matching record in table_c get the table_c.table_b_id value
Find the record in table_b which has a matching table_b.id value
For that matching record in table_b get the table_b.name value
In table_a, concatenate each matched name value into the corresponding table_a.result_column
Example:
Before the Query:
_______________________ _________________________________ ________________
| table_a: | | table_c: | | table_b: |
|---------------------| |-------------------------------| |--------------|
| id | result_column | | id | table_a_id | table_b_id | | id | name |
|-----|---------------| |-----|------------|------------| |-----|--------|
| 1 | | | 1 | 1 | 3 | | 1 | Kevin |
| 2 | | | 2 | 1 | 4 | | 2 | Jesse |
| 3 | | | 3 | 2 | 2 | | 3 | Karen |
----------------------- | 4 | 3 | 1 | | 4 | Tim |
| 5 | 3 | 5 | | 5 | Lauren |
--------------------------------- ----------------
After the Query:
_______________________ _________________________________ ________________
| table_a: | | table_c: | | table_b: |
|---------------------| |-------------------------------| |--------------|
| id | result_column | | id | table_a_id | table_b_id | | id | name |
|-----|---------------| |-----|------------|------------| |-----|--------|
| 1 | Karen, Tim | | 1 | 1 | 3 | | 1 | Kevin |
| 2 | Jesse | | 2 | 1 | 4 | | 2 | Jesse |
| 3 | Kevin, Lauren | | 3 | 2 | 2 | | 3 | Karen |
----------------------- | 4 | 3 | 1 | | 4 | Tim |
| 5 | 3 | 5 | | 5 | Lauren |
--------------------------------- ----------------
For absolute clarity, I understand that this is incredibly bad practice within a relational data-table. This is as far from normalization as one can get. I would never design a database like this. I was tasked with creating a custom column with a list of values purely for a business case.
The query you seem to want is:
select c.table_a_id, group_concat(b.name separator ', ')
from c join
b
on c.table_b_id = b.id
group by c.table_a_id;
If you actually want to update a, you can put this into an update statement:
update a join
(select c.table_a_id, group_concat(b.name separator ', ') as names
from c join
b
on c.table_b_id = b.id
group by c.table_a_id
) cb
on cb.table_a_id = a.id
set result_column = cb.names
Previous answer is close; but you also required that you only want the records matched in table C that are in A.
The first query does not meet this requirement; but the update statement does, as it will only update records in table A, if the id matches the table_a_id value pulled from table C.
Given what you said you wished for the end result, the update statement above would work.
If you wish to be explicit in your logic, just add a join from table A to table C.
select a.id, group_concat(b.name separator ', ')
from a
join c ON (a.id = c.table_a_id)
join b ON (c.table_b_id = b.id)
group by a.id;
I'm using MariaDB 5.5, but for this solution it would be same as for MySQL. I have two tables, first one contains galleries and second one contains info about files within each gallery. This is example of the table gallery:
+----+-------+-----+
| id | name | ... |
+----+-------+-----+
| 1 | test1 | ... |
| 2 | test2 | ... |
| 3 | test3 | ... |
| 4 | test4 | ... |
+----+-------+-----+
This is example of the table gallery_items:
+----+------+------------+-----+
| id | file | gallery_id | ... |
+----+------+------------+-----+
| 1 | img1 | 3 | ... |
| 2 | img2 | 2 | ... |
| 3 | img3 | 2 | ... |
| 4 | img4 | 1 | ... |
+----+------+------------+-----+
So I tried this code:
SELECT gallery.*, COUNT(gallery_items.id) AS items FROM gallery JOIN gallery_items WHERE gallery_items.gallery_id = gallery.id;
Well, I'm not really good with databases, so this is why I'm asking for help. This is my expected result:
+----+-------+-------+-----+
| id | name | items | ... |
+----+-------+-------+-----+
| 1 | test1 | 1 | ... |
| 2 | test2 | 2 | ... |
| 3 | test3 | 1 | ... |
| 4 | test4 | 0 | ... |
+----+-------+-------+-----+
you will need to GROUP BY in order for a COUNT to work
SELECT gallery.*, COUNT(gallery_items.id) AS items FROM gallery
LEFT JOIN gallery_items ON gallery_items.gallery_id = gallery.id
GROUP BY gallery.id, gallery.name
Description You may use the following query
SELECT
g.*,COUNT(gi.id) AS items
FROM
gallery g
LEFT JOIN gallery_items gi
ON g.id = gi.gallery_id
GROUP BY g.id;
Here is my query and it's not showing the 3rd row even though the tables contents match.
SELECT shopcategory_idcategory_name
FROM shopcategory
INNER JOIN category ON shopcategory_id=category_id;
Result:
================================================================
| shopcategory_id | shopcategory_shopid | category_name |
================================================================
| 1 | 1 | Gadgets |
| 2 | 2 | Analog Device |
================================================================
Here is my query that shows it has 3 rows
SELECT * FROM shopcategory;
Result:
===================================================================
| shopcategory_id | shopcategory_shopid | shopcategory_categoryid |
===================================================================
| 1 | 1 | 1 |
| 2 | 2 | 2 |
| 3 | 3 | 3 |
===================================================================
EDIT: Query for my category table
SELECT * category;
Result:
==============================================
| category_id | category_name |
==============================================
| 1 | Gadgets |
| 2 | Analog Device |
| 3 | Beauty |
| 4 | Keyboard |
| 5 | Instruments |
| 6 | Monitor |
| 7 | Chairs |
==============================================
You should use LEFT JOIN here instead and add aliases for tables that you are joining on, like this:
SELECT
tableName1.shopcategory_id,
tableName1.category_name,
tableName2.category_id
FROM
tableName1 as tb1
LEFT JOIN
tableName2 AS tb2
ON
tb1.shopcategory_id = tb2.category_id
GROUP BY
tb1.shopcategory_id;
structure:
tbl 1
|car_id(PK)| make | model | year |
-----------------------------------
| 1 | Toyot | Camry | 1999 |
| 2 | Honda | Civic | 2005 |
tbl 2
|img_id(PK)| car_id| img_link |
------------------------------------
| 1 | 1 | tcamry1.jpeg |
| 2 | 1 | tcamry2.jpeg |
| 3 | 1 | tcamry3.jpeg |
| 4 | 2 | hcivic1.jpeg |
| 5 | 2 | hcivic2.jpeg |
My query:
SELECT *
FROM cars c
LEFT JOIN imgs g
ON c.car_id=g.car_id
WHERE 1
Result:
|img_id(PK)| car_id| make | model | year | img_link |
-----------------------------------------------------------
| 1 | 1 | Toyot | Camry | 1999 | tcamry1.jpeg |
| 2 | 1 | Toyot | Camry | 1999 | tcamry2.jpeg |
| 3 | 1 | Toyot | Camry | 1999 | tcamry3.jpeg |
| 4 | 2 | Honda | Civic | 2005 | hcivic1.jpeg |
| 5 | 2 | Honda | Civic | 2005 | hcivic2.jpeg |
I need to get 1 row for each car and have WHERE clause with something like lowest img_id value out of all img_id related to the same car.
Result I want:
|img_id(PK)| car_id| make | model | year | img_link |
-----------------------------------------------------------
| 1 | 1 | Toyot | Camry | 1999 | tcamry1.jpeg |
| 4 | 2 | Honda | Civic | 2005 | hcivic1.jpeg |
Thank you.
UPDATE:
I need something along these lines :-/
SELECT g.id, c.car_id, c.mc_make, c.mc_model, c.mc_year, c.mc_desc
FROM mycars c
INNER JOIN (SELECT * FROM mycars_gallery g WHERE )
ON c.car_id=g.car_id
WHERE g.id = min(g.id)
Try:
SELECT MIN(b.img_id), a.car_id, a.make, a.model, a.year, b.img_link
FROM cars a
LEFT JOIN imgs b ON a.car_id = b.car_id
GROUP BY a.car_id, a.make, a.model, a.year ;
Demo: http://sqlfiddle.com/#!2/1469f/15
Hope this helps.
SELECT *
FROM cars c
LEFT JOIN imgs g
ON c.car_id=g.car_id
WHERE img_id IN(SELECT MIN(img_id)) GROUP BY model
SELECT *
FROM cars c
LEFT JOIN imgs g
ON c.car_id=g.car_id
WHERE 1
GROUP BY g.img_link;
try this.. not sure though.
I have two tables like below,
mysql> select * from Books ;
+----+------+------------+----------+----------+
| id | name | author_name| category | category2|
+----+------+------------+----------+----------+
| 1 | 1 | Steve | CT001 | CT003 |
| 2 | 2 | John | CT002 | CT002 |
| 3 | 3 | Larry | CT003 | CT002 |
| 4 | 3 | Michael | CT004 | CT004 |
| 5 | NULL | Steven | CT005 | CT005 |
+----+------+------------+----------+----------+
mysql> select * from Codemst ;
+----+------+------------+
| id | code | name |
+----+------+------------+
| 1 | CT001| fiction |
| 2 | CT002| category1 |
| 3 | CT003| etc |
| 4 | CT004| etc2 |
| 5 | CT005| etc3 |
+----+------+------------+
I want to get human readable category name when I query like "select * from Books;"
If there was only one category in the Books table, I think I can use "Join" but, in this case what can I do?
select * from Books b
Inner Join Codemst c1 on b.category = c1.code
inner join codemst c2 on b.category2 = c2.code;
c1.name will hold the readable category, and c2.name the readable category2