Where is the LINQ to SQL statement (1)

• where operation

Application scenario: Filter, Query and other functions.

Description: Similar to where in the SQL command, it is scoped to filter, and the judging condition is the clause that is followed by it.

The where operation consists of 3 forms, namely the simple form, the relationship condition form, and the first () Form. The following examples are used for example:

1. Simple form:

Example: use where to filter customers in London

var =  from inch db. Customers  where= =  "London"  select C;　　

Again: Filter employees who are employed after 1994 years or later:

var =  from inch db. Employees  where>=DateTime(199411) Select e;　　

2. Relationship Condition form:

Filter products with inventory levels below the order point level but not broken:

var =  from inch db.  Products where<=&&  ! p.discontinued  select p;　　

Filter out products with UnitPrice greater than 10 or discontinued:

var =  from inch db. Products where>| | p.discontinued Select p;　　

The following example calls a two-time where to filter out products that have unitprice greater than 10 and that have been discontinued.

vardb. Products. Where (p=> 10m). Where (p=p.discontinued);

3.First () Form:

Returns an element in the collection, with the essence of adding top (1) to the SQL statement.

Simple usage: Select the first shipper in a table.

= db. Shippers.first ();

Element: Select a single customer with CustomerID as "Bonap"

= = == "Bonap");

Condition: Select an order with freight greater than 10.00:

Order = = > 00M);

Where is the LINQ to SQL statement (1)