sql count distinct values

("", ""). Replace (")", ")-");Switch (country){Case "USA":Return "1-" + Phone;Case "UK":Return "44-" + Phone;Defaultreturn Phone;}}The following also uses this method to convert phone numbers to international format and create XDocumentXDocument doc = new XDocument (New XElement ("Customers", from C in DB. Customerswhere c.country = = "UK" | | C.country = = "USA"Select (New XElement ("Customer",New XAttribute ("CustomerID", C.customerid),New XAttribute ("CompanyName", C.companyname),New XAttrib

Label:Http://www.w3school.com.cn/sql/sql_distinct.asp SQL SELECT DISTINCT Keyword DISTINCT is used to return only different values. Grammar: SELECT DISTINCT column_name from table_name Instance: "Orders" table Co

In the table, duplicate values may be included. That's not a problem, but sometimes you might want to just list different values (distinct). Keyword DISTINCT is used to return only different values, to filter duplicate data, or to remove duplicate data after the field list h

>= Greater than or equal Less than or equal Between Within a range Like Search for a pattern Note: In some versions of SQL, the operator For example SELECT * from Persons WHERE city = ' Beijing ' 　　 Use of quotation marks Note that the above condition values in the example use single quotes around the

SQL distinct SQL distinct usage You can use the DISTINCT keyword to remove rows with duplicate query results. Different queries are very useful. You just want to know whether a value table exists and you are not interested in how many times. Different statements can only b

This chapter explains the SELECT DISTINCT statement. SQL SELECT DISTINCT Statement In a table, you might include duplicate values. This is not a problem, but sometimes you may want to list only the different values (distinct).

Tags: any body different statement class BER select repeat ProblemSQL SELECT DISTINCT StatementIn the table, duplicate values may be included. That's not a problem, but sometimes you might want to just list different values (distinct). Keyword DISTINCT is used to return only

SQL SELECT DISTINCT Syntax and usage tutorial This chapter will explain the choice of discrete speakers.Select a different declaration in SQLIn one table, some columns may contain duplicate values. This is not a problem, however, sometimes you will want to list only the different (different) values on the table.

Label:In the table, duplicate values may be included. That's not a problem, but sometimes you might want to just list different values (distinct). Keyword DISTINCT is used to return only different values.Table A:Example 1Select distinct name from AThe following results are p

>20Truncate table student functions like delete from studentis to delete all the data in the student table, the difference is:1. The TRUNCATE statement is very efficient. Because the truncate operation uses minimally logged logging, the efficiency is higher. For millions of data to be deleted using truncate for only a few seconds, while using delete takes several hours.2. The TRUNCATE statement resets the auto-numbering in the table to the default value (where it reverts to the seed), and after