how to sql query

Select A.name as table name, b.name as column name, c.name as type, b.max_length as Byte count, b.precision As Integer, B.scale as decimal from Sys.tables a INNER JOIN Sys.columns B on a.object_id=b.object_id inner join Sys. Types C on

In many of the projects that have been done, we find that no matter what the table, every select must add Nolock (or with (NOLOCK)), it seems to have been institutionalized a thing. The leading high man explained that adding nolock can improve the

When writing stored procedures, you often encounter the need to splice SQL statements, generally only to perform the post-stitching statements using EXEC (@sql).Today, a stored procedure needs to get the results of a dynamic SQL query.Requirement

In recent projects, a shell script is required to perform SQL operations on a database and convert the results to txt, and the filter results are tab-delimited and saved to a remote server for other people to use in Excel to read content in

Problem Description:Neither in SQL 2000, nor in SQL 2005, does the aggregate function of the string be provided,Therefore, when we are dealing with the following requirements, it will be more troublesome:There are table TB, as follows:ID value----- -

http://blog.csdn.net/c517984604/article/details/7052186 [ERR] 1242-subquery returns more than 1 row--Indicates that the subquery returned multiple rows of dataFor example:SELECT * FROM table1 where table1.colums= (select columns from

query Table StructureDESC table name ;querying all RecordsSELECT * from table name;querying a specified recordSelect Name,age,birthday from table name;querying some fields for different records (DE-weight)SELECT DISTINCT name,birthday from table

A simple example of the WITH AS clause was previously seen in 2 books, and no relevant information was found on the web.Today I think of a summary, the main explanation is as follows:"Big Table Batch Update""Large table Batch Delete""Completely

1.Three-valued Logic: True/false/unknown2.A missing value (NULL) is compared to another value, and the logical result is unknownUnkown:null > 42/null = null/x + NULL > Y/...3.Not TRUE = FALSENot FALSE = TRUENot UNKNOWN = UNKNOWN4.All query filters

The 1.ORDER by clause is executed after the SELECT clause.The 2.ORDER by clause is the last clause executed.Multiple sort fields can be set in the 3.ORDER by clause;4.ORDER by has two sort modes: desc descending, ASC ascending (default, can not be

UPDATE ht_plan_triptime pptSET ppt.lock_status = ' 1 'WHERE ppt.lock_status <> ' 1 'and ppt.plan_id =?and Ppt.allowed_person > 0and Ppt.allowed_person COUNT (*)From Ht_tourist_team_info tiINNER JOIN ht_order_info oi on oi.order_id = ti.order_idINNER

1. Table Definition(1) If the string field is often needed, can be redundant, otherwise do not redundant(2) A field that is often required as a where query condition can be indexed, but too many indexes affect the performance at write time(3)

1. To optimize the query, avoid full-table scanning as far as possible, and first consider establishing an index on the columns involved in the Where and order by.2. You should try to avoid null values in the WHERE clause to judge the field,

SQL in thinkphp provides the following query statementsString sql safety factor is too lowFor example with the M method use:$user = M (' user ');Var_dump ($user->where (' id=1 | | user= "Crayon Small New" ')->select ());It's much safer to use an

1. View table structureSQL>DESC EMP;2. Querying all ColumnsSql>select * from EMP;3. Querying a specified columnSql>select empmo, ename, Mgr from EMP;Sql>select DISTINCT Mgr from EMP; Show only items with different results4. Querying a specified

--QueryDay：SELECT * FROM info whereDateDiff (dd,datetime,getdate()) =0 --Query within 24 hours : Select * from info where datediff (Hh,datetime,getdate ())   -- Query this week 's recordsSELECT * from info where datediff

Target: Implement the following, passing SQL through Spring JDBC, querying the Java data Objects that meet the criteria:Pojo: Public classZmtest { Publiczmtest () {//TODO auto-generated Constructor stub } PrivateInteger ID; PrivateString name;

1 Use [Golf73_bjsy]2 GO3 /** * * * object:storedprocedure [dbo]. [P_frontcounter_getcheckinfobycondition] Script date:11/18/2014 11:38:50 * * * * **/4 SETAnsi_nulls on5 GO6 SETQuoted_identifier on7 GO8 -- =========================================

Database UserInfoDelete duplicate user name delete duplicate username phone number the same user name phone number only one user is reserved01. Querying duplicate data based on multiple fieldsWith Data1 as (Select Mobilephone,name from UserInfoGROUP

Original: http://www.cnblogs.com/sammon/archive/2012/05/10/2494362.htmlTest tables and test dataCREATE TABLE Testtitle (Name VARCHAR (10),Titlevarchar (10));INSERT into Testtitle VALUES (' Zhang San ', ' Programmer ');INSERT into Testtitle VALUES ('