大约有 10,000 项符合查询结果（耗时：0.0195秒） [XML]
Good PHP ORM Library?
...er/Sybase, Oracle, PostgreSQL, etc.
/* SQL */
CREATE TABLE products (
product_id INTEGER,
description VARCHAR(128),
PRIMARY KEY (product_id)
);
/* PHP */
// Create
$product=new Axon('products'); // Automatically reads the above schema
$product->product_id=123;
$product->descripti...
selecting unique values from a column
...s per date as JSON.
SELECT `date`,
CONCAT('{',GROUP_CONCAT('{\"id\": \"',`product_id`,'\",\"name\": \"',`product_name`,'\"}'),'}') as `productsJSON`
FROM `buy` group by `date`
order by `date` DESC
product_id product_name date
| 1 | azd | 2011-12-12 |
| 2 | xyz |...
What is the difference between partitioning and bucketing a table in Hive ?
...e performance and increases the overhead.
select * from sales_table where product_id='P1'
To avoid full table scan and to read only the records related to product_id='P1' we can partition (split hive table's files) into multiple files based on the product_id column. By this the hive table's file ...
How to implement a many-to-many relationship in PostgreSQL?
...nition language) statements could look like this:
CREATE TABLE product (
product_id serial PRIMARY KEY -- implicit primary key constraint
, product text NOT NULL
, price numeric NOT NULL DEFAULT 0
);
CREATE TABLE bill (
bill_id serial PRIMARY KEY
, bill text NOT NULL
, billdate da...
How to become an OpenCart guru? [closed]
...e cart including options, discounted prices, etc.
$this->cart->add( $product_id, $qty = 1, $options = array()) - Allows you to add a product to the cart
$this->cart->remove( $key ) - Allows you to remove a product from the cart
$this->cart->clear() - Allows you to remove all produc...
Possible to do a MySQL foreign key to one of two possible tables?
... key that references a central Products table.
CREATE TABLE Products (
product_id INT PRIMARY KEY
);
CREATE TABLE FiltersType1 (
filter_id INT PRIMARY KEY,
product_id INT NOT NULL,
FOREIGN KEY (product_id) REFERENCES Products(product_id)
);
CREATE TABLE FiltersType2 (
filter_id INT PR...
PostgreSQL DISTINCT ON with different ORDER BY
...ddress_id, max(purchased_at) max_purchased_at
FROM purchases
WHERE product_id = 1
GROUP BY address_id
) t2
ON t1.address_id = t2.address_id AND t1.purchased_at = t2.max_purchased_at
ORDER BY t1.purchased_at DESC
A more PostgreSQL-oriented solution based on @hkf's answer:
SELECT * FROM...
How do I use cascade delete with SQL Server?
... data is deleted when the parent data is deleted.
CREATE TABLE products
( product_id INT PRIMARY KEY,
product_name VARCHAR(50) NOT NULL,
category VARCHAR(25)
);
CREATE TABLE inventory
( inventory_id INT PRIMARY KEY,
product_id INT NOT NULL,
quantity INT,
min_level INT,
max_level INT,
...
MySQL - UPDATE query based on SELECT Query
... the problem, which I thought might be useful.
I needed to populate the product_id field in the activities table, where activities are numbered in a unit, and units are numbered in a level (identified using a string ??N), such that one can identify activities using an SKU ie L1U1A1. Those SKUs a...
MySQL foreign key constraints, cascade delete
...ATE TABLE categories_products (
category_id int unsigned not null,
product_id int unsigned not null,
PRIMARY KEY (category_id, product_id),
KEY pkey (product_id),
FOREIGN KEY (category_id) REFERENCES categories (id)
ON DELETE CASCADE
ON UPDATE CASCADE,
FOREIGN K...