iif sql

Tags: primary key first break range Ror add comment art DropSQL PRIMARY KEY ConstraintThe PRIMARY KEY constraint uniquely identifies each record in a database table. The primary key must contain a unique value. Primary key columns cannot contain NULL values. Each table should have a primary key, and each table can have only one primary key.SQL PRIMARY KEY Constraint on CREATE TABLEThe following SQL creates the PRIMARY KEY constraint in the "id_p" colu

I often develop asp, but I am not very clear about the detailed statements. Here is a brief introduction. Generally Rs. open SQL, conn, are used to read data. Modify data: rs. open SQL, conn, 1, 3 Delete data: You can directly delete data such as conn.exe cute ("delete * from new where id = 1. Rs. Open Syntax: rs. Open Source, ActiveConnection, CursorType, LockType Source is an

Label: conn =mysqljdbcutils.getconnection (); Statement PS=conn.createstatement (); Ps.addbatch ("Truncate Qb_showcount_asite_copy"); Ps.executebatch (); String Srcsql= "SELECT Convert" (Unhex (Hex (CONVERT (Community using latin1)) using UTF8) as Community, PID from Qb_menbercmmsets_list whe Re site=7 "; stmt=conn.preparestatement (Srcsql); RS=Stmt.executequery (); Above is the empty command that executes before the following SQL statement executes//

Today to query their own installed sqlserver2008 is R2 version, search the next, found that a lot of people query this problem, now recorded as follows, through the version of the command queryAlso understand the older brother SQL Server version of the good, a look is very clear, record 1. View SQL Server 2005/2008 version number The code is as follows Copy Code Select SERVERPR

SQLServer how to use the T-SQL command to query a database in which tables, convenient table operations, need friends can refer to the next SQLServer how to use the T-SQL command to query a database in which tables, convenient table operations, need friends can refer to the next 1. query all tables in SQL: Select TABLE_NAME FROM database name. INFORMATION_SCHE

SQL Server database management common SQL and T-SQL statements 1. view the database version Select @ version 2. view the operating system parameters of the machine where the database is located Exec master .. xp_msver 3. view database startup parameters Sp_configure 4. view the database startup time Select convert (varchar (30), login_time, 120) from master .. sy

SQL connections (2) -- SQL Reading Notes, SQL Reading Notes Chapter 1 in SQL Learning Guide 1.4 outer connections In multi-table join, the connection condition may not match all rows in the table. For example, when the account table is connected to the customer table, the value of the cust_id column in the account tabl

SQL UNION operatorThe UNION operator is used to combine the result set of two or more SELECT statements.Note that the SELECT statement inside the UNION must have the same number of columns. The column must also have a similar data type. Also, the order of the columns in each SELECT statement must be the same.SQL UNION SyntaxSELECT column_name (s) from Table_name1unionselect column_name (s) from table_name2Note: By default, the UNION operator chooses a

format, note that the two should be a corresponding. such as To_date (' 2004-11-27 13:34:43 ', ' yyyy-mm-dd hh24:mi:ss ') will get specific time String handler function: Select To_number (SUBSTR (rain_1,0,2), ' xx ') from Obs (i) Access database You know there is an IIf function in Access that simplifies a judgment assignment sequence into an expression, such asIIF (a>b,1,2), if it does a>b then the result gives 1, otherwise it is 2. It's really

It is useful to query all records for this quarter based on the current date. Here are two SQL statements for access quarterly query records for your reference. 1, querying all records for the current quarterSELECT * FROM news where DATEPART (' Q ', time) = DATEPART (' Q ', now ()) and DATEPART (' yyyy ', time) = DATEPART (' yyyy ', now ()) 2, summarize and display all data quarterlySELECT IIf (month) in

Static SQL, dynamic SQL, and static SQL Static 1. Common MemberCommon members belong to objects.Call with object 2. Static membersStatic members belong to the classCalled by Class Name Class FenBi{Public int length; // common memberPublic string color ;//} Static keywords Static methods cannot contain common members. The common method can contain static members.

1. query all tables in SQL: Select TABLE_NAME FROM database name. INFORMATION_SCHEMA.TABLES Where TABLE_TYPE = 'base table' after execution, you can see the names of all tables created by yourself in the database. 2. query all tables and columns in SQL: Select dbo. sysobjects. name as Table_name, dbo. syscolumns. name AS Column_name FROM dbo. syscolumns inner join dbo. sysobjects ON dbo. syscolumns. id

Complex SQL Split optimizationSplitting SQL is one of the most effective methods of performance optimization, which is to break down complex SQL into simple SQL by a certain logic, and finally execute an equivalent logic with the help of temporary tables, and have achieved efficient execution. I've been trying to write

In fact, this is also a problem at work. To tell the truth, I am not willing to do it myself. I also want to write statements for queries, but I have not thoroughly studied this kind of information,Write SQL statements in JavaProgramAt the same time, I chose to be lazy. First, if it is golden, of course there is no need to say that the Direct Write statement is similar to select. If it is PL/SQL, it is not

1. Query all tables in sql: Select table_name from database name. Information_schema. Tables Where table_type= ' BASE table ' is executed, you can see the names of all the tables in the database that belong to you 2. Query all tables and columns in sql:Select Dbo.sysobjects.name as TABLE_NAME, dbo.syscolumns.name as column_name from Dbo.syscolumns INNER JOIN dbo.sysobject s on dbo.syscolumns.id = Dbo.sysobjects.id Where (dbo.sysobjects.xtype = '

' Teacher ' (' Tid ' int (one) not NULL auto_increment,' Name ' varchar (DEFAULT NULL),' job_title ' varchar DEFAULT NULL,' Major ' varchar DEFAULT NULL,PRIMARY KEY (' tid ')) Engine=innodb auto_increment=6 DEFAULT Charset=utf8; Tutor Table Data Insert INTO ' teacher ' (' tid ', ' name ', ' Job_title ', ' major ') values (1, ' Shen ', ' Professor ', ' image '), (2, ' Liu ', ' Professor ', ' database '), (3, ' Yellow ', ' associate Professor ', ' machine learning '), (4, ' Jarvis

SQL % found, SQL % notfound, SQL % rowcountWhen executing the DML (insert, update, delete) statement, you can use the following three implicit cursors (the cursor is an area in the memory that maintains the query results, which is opened when DML is run, when it is finished, use SQL % isopen to check whether it is enab

Tags: process variable assignment multiple meanings have a counter target based on nullI. T-SQL overviewThe programming language that SQL Server uses to manipulate the database is Transaction-sql, or T-SQL. T-SQL differs from PL/SQL