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;
Related
I'm creating e-commerce web site using MySQL. I have successfully created and inserted data to database.
Here is my database schema
table: categories table: product_types
+----+--------------+ +----+-------------+------------+
| id | name | | id | category_id | name |
+----+--------------+ +----+-------------+------------+
| 1 | Electronics | | 1 | 1 | Smartphone |
| 2 | Fashion | | 2 | 1 | Speakers |
+----+--------------+ +----+-------------+------------+
table: products
+----+-----------------+-------------+-------------------+-------+
| id | product_type_id | category_id | name | price |
+----+-----------------+-------------+-------------------+-------+
| 1 | 1 | 1 | Samsung Galaxy A3 | 300 |
| 2 | 1 | 1 | Samsung Galaxy A7 | 400 |
+----+-----------------+-------------+-------------------+-------+
table: options table: option_values
+----+-----------------+-------+ +----+-----------+------------+
| id | product_type_id | name | | id | option_id | name |
+----+-----------------+-------+ +----+-----------+------------+
| 1 | 1 | RAM | | 1 | 1 | 512 MB |
| 2 | 1 | Screen| | 2 | 1 | 1 GB |
| 3 | 1 | OS | | 3 | 3 | Android 5 |
+----+-----------------+-------+ | 4 | 3 | Android 6 |
| 5 | 2 | HD |
| 6 | 2 | FHD |
+----+-----------+------------+
table: product_option_values
+----+------------+-----------+-----------------+
| id | product_id | option_id | option_value_id |
+----+------------+-----------+-----------------+
| 15 | 1 | 1 | 1 |
| 16 | 1 | 2 | 5 |
| 17 | 1 | 3 | 3 |
| 18 | 2 | 1 | 2 |
| 19 | 2 | 2 | 6 |
| 20 | 2 | 3 | 4 |
+----+------------+-----------+-----------------+
Search must trigger through name column of each table and return name and price from products table.
The problem is that I don't know how to perform full text search joining all that tables.
Is there any easy way to do it?
You need a query that LEFT JOINs on each table to search with a condition based on fulltext search function MATCH, with a WHERE clause to filter out non-matching records. The SELECT DISTINCT ensures that you will not see duplicates.
We need to adjust manually the JOIN criteria from each table to products : option_values is the most complicated case as it does not directly references products (an additional join on product_option_values is needed, aliased pov below.
SELECT DISTINCT p.name, p.price
FROM
products p
LEFT JOIN categories c
ON MATCH(c.name) AGAINST('foo' IN NATURAL LANGUAGE MODE)
AND c.id = p.category_id
LEFT JOIN product_types pt
ON MATCH(pt.name) AGAINST('foo' IN NATURAL LANGUAGE MODE)
AND pt.category_id = p.category_id
LEFT JOIN options o
ON MATCH(o.name) AGAINST('foo' IN NATURAL LANGUAGE MODE)
AND o.product_type_id = p.product_type_id
LEFT JOIN product_option_values pov
ON pov.product_id = p.id
LEFT JOIN option_values ov
ON MATCH(ov.name) AGAINST('foo' IN NATURAL LANGUAGE MODE)
AND ov.id = pov.option_value_id
WHERE
COALESCE(c.id, pt.id, o.id, ov.id) IS NOT NULL
this is my first time posting here. I don't seem to find the answer to my problem.
So... I'm arranging a DB for a school project, a cookbook that only shows recipes that can be made with existing elements from the "shelf".
These ingredients have to have an exact ingredients match.
user:
+---------------+------+----------+----------+
| email | name | lastname | password |
+---------------+------+----------+----------+
| pal#mail.com | John | Potato | password |
| they#mail.com | Mary | Carrot | password |
+---------------+------+----------+----------+
shelf:
+---------+------------+---------------+
| shelfID | ingredient | user |
+---------+------------+---------------+
| 1 | 1 | pal#mail.com |
| 2 | 2 | pal#mail.com |
| 3 | 3 | pal#mail.com |
| 4 | 4 | pal#mail.com |
| 5 | 10 | they#mail.com |
| 6 | 12 | they#mail.com |
+---------+------------+---------------+
This is my recipe_ingredient relationship table
recipe_ingredient:
+--------+------------+
| recipe | ingredient |
+--------+------------+
| 1 | 1 |
| 1 | 2 |
| 1 | 4 |
| 1 | 10 |
| 2 | 1 |
| 2 | 2 |
| 2 | 3 |
| 2 | 4 |
| 3 | 2 |
| 3 | 3 |
| 3 | 15 |
+--------+------------+
I've tried this query:
SELECT
rec_ing.recipe, shf.ingredient, shf.user
FROM
recipes_ingredients AS rec_ing
INNER JOIN
shelf AS shf ON rec_ing.ingredient = shf.ingredient
INNER JOIN
users AS usr ON shf.user = usr.email
WHERE
usr.email = 'pal#mail.com'
that returns this table:
+--------+------------+--------------+
| recipe | ingredient | user |
+--------+------------+--------------+
| 1 | 1 | pal#mail.com |
| 1 | 2 | pal#mail.com |
| 1 | 4 | pal#mail.com |
| 2 | 1 | pal#mail.com |
| 2 | 2 | pal#mail.com |
| 2 | 3 | pal#mail.com |
| 2 | 4 | pal#mail.com |
| 3 | 2 | pal#mail.com |
| 3 | 3 | pal#mail.com |
+--------+------------+--------------+
Although it's true that the Recipe 1 contains ingredients from my shelf, it's also missing Ingredient 10
+--------+------------+
| recipe | ingredient |
+--------+------------+
| 1 | 1 |
| 1 | 2 |
| 1 | 4 |
| 1 | 10 |
| ... | ... |
+--------+------------+
I'm trying to only get this kind of result set.
+--------+------------+
| recipe | ingredient |
+--------+------------+
| 2 | 1 |
| 2 | 2 |
| 2 | 3 |
| 2 | 4 |
+--------+------------+
Because Recipe 2 contains all elements from my shelf
I have been going around all day with this problem ... What could be missing?
This is a bit tricky, because you need to aggregate your current query by recipe, but you also need the original query to get back the full records. Sadly, MySQL does not support common table exprrssions or other features which could give us a less verbose query.
SELECT
rec_ing.recipe,
shf.ingredient,
shf.user
FROM recipes_ingredients AS rec_ing
INNER JOIN shelf AS shf
ON rec_ing.ingredient = shf.ingredient
INNER JOIN users AS usr
ON shf.user = usr.email
INNER JOIN
(
SELECT rec_ing.recipe
FROM recipes_ingredients AS rec_ing
INNER JOIN shelf AS shf
ON rec_ing.ingredient = shf.ingredient
LEFT JOIN users AS usr
ON shf.user = usr.email
WHERE
usr.email = 'pal#mail.com'
GROUP BY rec_ing.recipe
HAVING COUNT(usr.email) = COUNT(*)
) t
ON rec_ing.recipe = t.recipe
WHERE
usr.email = 'pal#mail.com'
The basic strategy here is to just do one additional join to a subquery which identifies all recipes where every ingredient belongs to a given user. The critical part is the following:
HAVING COUNT(usr.email) = COUNT(*)
This checks that the total number of rows for a given recipe matches the number of rows which have been assigned to a given user.
Three table as follow
mysql> select * from food;
+--------+------+-------+
| foodid | name | price |
+--------+------+-------+
| 1 | 雞 | 100 |
| 2 | 鴨 | 200 |
| 3 | 魚 | 300 |
| 4 | 肉 | 400 |
+--------+------+-------+
4 rows in set
mysql> select * from drink;
+---------+------+-------+
| drinkid | name | price |
+---------+------+-------+
| 1 | 紅茶 | 50 |
| 2 | 綠茶 | 100 |
| 3 | 奶茶 | 150 |
+---------+------+-------+
3 rows in set
mysql> select * from order_table;
+----+-----------+--------+---------+------------+-------------+-------------+
| id | user_name | foodid | drinkid | food_count | drink_count | total_price |
+----+-----------+--------+---------+------------+-------------+-------------+
| 2 | 小明 | 3 | 2 | 2 | 2 | 0 |
| 3 | 小華 | 1 | 1 | 1 | 8 | 0 |
| 4 | 小英 | 1 | 3 | 3 | 3 | 0 |
| 6 | 小a | 2 | 1 | 4 | 6 | 0 |
| 7 | 小b | 2 | 2 | 5 | 4 | 0 |
| 8 | 小c | 2 | 3 | 6 | 10 | 0 |
| 9 | 大A | 3 | 1 | 9 | 8 | 0 |
| 10 | 大B | 3 | 2 | 5 | 4 | 0 |
| 11 | 大C | 3 | 3 | 10 | 3 | 0 |
+----+-----------+--------+---------+------------+-------------+-------------+
foodid in order_table is link to foodid in food table,
drinkid in order_table is link to drinkid in drink table,
Now, I want to calculate total price,
Total_price =
order_table.foodid(food.price in food table) * order_table.food_count +
order_table.drinkid(drink.price in drink table) * order_table.drink_count;
So, let me knowlege the command to update total price
thx a lot.
The reason why I used LEFT JOIN on the following query is because I assumed that some orders may only contain drinks or foods.
UPDATE order_table a
LEFT JOIN food b
ON a.foodid = b.foodID
LEFT JOIN drink c
ON a.drinkID = c.drinkID
SET a.total_price = (a.food_count * COALESCE(b.price, 0) +
a.drink_count * COALESCE(c.price, 0))
SQLFiddle Demo
To further gain more knowledge about joins, kindly visit the link below:
Visual Representation of SQL Joins
Something like this should be close:
SELECT COALESCE(F.Price,0)*OT.Food_Count+COALESCE(D.Price,0)*OT.Drink_Count Total_price
FROM Order_Table OT
LEFT JOIN Food F ON OT.FoodId = F.FoodId
LEFT JOIN Drink D ON OT.DrinkId = D.DrinkId
And to actually update that column:
UPDATE Order_Table OT
LEFT JOIN Food F ON OT.FoodId = F.FoodId
LEFT JOIN Drink D ON OT.DrinkId = D.DrinkId
SET OT.Total_Price = COALESCE(F.Price,0)*OT.Food_Count+COALESCE(D.Price,0)*OT.Drink_Count
I have five mysql tables. shops
+----+--------------+--------------+
| id | name | address |
+----+--------------+--------------+
| 1 | Shop1 | Street1 |
| 2 | Shop2 | Street2 |
| 3 | Shop3 | Street3 |
| 4 | Shop4 | Street4 |
+----+--------------+--------------+
fruits
+----+--------------+--------------+
| id | fruit | price |
+----+--------------+--------------+
| 1 | Bannana | 2.5 |
| 2 | Apple | 2.1 |
| 3 | Orange | 1.8 |
| 4 | Plum | 2.2 |
+----+--------------+--------------+
availability
+----+--------------+--------------+
| id | shop_id | fruit_id |
+----+--------------+--------------+
| 1 | 1 | 2 |
| 2 | 2 | 2 |
| 3 | 1 | 3 |
| 4 | 2 | 1 |
+----+--------------+--------------+
shop_activity
+----+--------------+--------------+--------------+
| id | shop_id | user_id | status |
+----+--------------+--------------+--------------+
| 1 | 2 | 1 | 1 |
| 2 | 3 | 2 | 1 |
| 3 | 1 | 2 | 2 |
| 4 | 2 | 2 | 1 |
+----+--------------+--------------+--------------+
users
+----+--------------+
| id | name |
+----+--------------+
| 1 | Peter |
| 2 | John |
+----+--------------+
I have query
SELECT
availability.shop_id,
shops.name
FROM availability
LEFT JOIN shops
ON availability.shop_id=shops.id
WHERE
fruit_id = 2
As a result I get name list of shops where fruit with id 2 (apple) is available.
What should I do so that I can include shop_activity table in query to get user's status if users.id = 1 beside proper shop. Something like this...
Shop1, NULL
Shop2, status: 1
You could try something like this:
SELECT
availability.shop_id,
shops.name,
shop_activity.status
FROM availability
LEFT JOIN shops
ON availability.shop_id=shops.id
LEFT JOIN shop_activity
ON shop_activity.shop_id = availability.shop_id
and shop_activity.user_id = 1
WHERE
fruit_id = 2
SELECT
availability.shop_id,
shops.name
FROM shops
LEFT JOIN availability ON availability.shop_id=shops.id
LEFT JOIN shop_activity ON shop_activity .shop_id=shops.id
WHERE
fruit_id = 2
and users.id=1
try making shops as the first table in left join
Try the following:
SELECT shops.name, shop_activity.status
FROM shops
INNER JOIN availability ON availability.shop_id = shops.id
AND availability.fruit_id = 2
LEFT JOIN shop_activity ON shops.shop_id = shop_activity.shop_id
AND shop_activity.user_id = 1
This should give you a row for every shop with apples, but the status will show as null for shops where the user has no activity, otherwise shows the status of that user.
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