assign value to variable in sql select statement

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.Grammar:SELECT DISTINCT column name from table nameUsing DISTINCT KeywordsIf you want to pick all the values from the company column, we need to use the SELECT statement:

SQL statement select like usage In SQL Structured Query Language, like statements play a vital role.The syntax format of the like statement is: Select * from table name where field name like corresponding

The syntax is as follows:1. Description: copy a table (only copy structure, source table name: a new table name: B) (access available)Method 1: Select * into B from a where 1 Method 2: Select top 0 * into B from 2. Description: copy a table (copy data, source table name: A target table name: B) (access available)Insert into B (a, B, c) Select D, E, F from; 3. Cr

If there is a t_user data table in this way, the table ID increases automatically, but the IDs in the data table are not guaranteed to be continuous. Write an SQL statement, query the data between the n-th record and the M-th record (M> N> 0, all smaller than the total number of records in the data table) The idea is as follows: First, find the ID of the nth record and the nth record. Obtain the ID

Tags: selectall http User space result 1.0 sele character ttyPackage the SQL query statement "SELECT * from User" as a configuration file with MyBatis Define an XML mapping file, and the file name is known as the name. such as User-mapper.xml, the file contents are as follows: Public "-//mybatis.org//dtd Mapper 3.0//en" "Http://mybatis.org/dtd/mybatis-3-mapper.

In a list page need to call the article content and video content, but also to the corresponding data to do paging, after the milking milk found {dede:listsql sql= "select * from ' dede_archives ', ' Dede_ Addonarticle ' WHERE Dede_archives.typeid = Dede_addonarticle.typeid and Dede_archives.typeid = ~typeid~ ' pagesize= ' 10 '} This label, when give typeid passed fixed

Useful firstCopy codeThe Code is as follows:Use DatabaseUpdate news set author = 'jb51 'where author is nullIf you are incorrect, it means that you have made a mistake. Taking a closer look, we strongly recommend that you back up the database before performing operations. Note: replace NULL with the specified replacement value. Syntax: ISNULL (check_expression, replacement_value) Parameters: Check_expression: The expression to be checked for NULL. Che

Label:Source: http://www.aimks.com/sql-update-the-select-statement-application.html QL Update SELECT statement The most common update syntax is: UPDATE table_name SET = = VALUE If my update