not exists teradata

Tags: style blog http ar os using SP on dataText: The exists in the SQL drip 35-sql statementFor example, in the Northwind database there is a query for select C.customerid,companyname from Customers C where EXISTS (select OrderID from Orders o where O . Customerid=c.customerid) How does this exists work? The subquery returns the OrderID field, but the outside qu

SQL exists, in, sqlexistsinTips:1. When the External table is a large table and the inner table is a small table, use exist2. When the External table is a small table and the internal table is a large table, the inExample: The External table is large and the internal table is small.Create table outTable (id1 int );Insert into outtable select generate_series );Create table inTable (id1 int );Insert into inTable values (1), (10000), (100000), (1000000 )

Exists indicates the existence quantizer. A subquery with an exists predicate does not return any data, but only generates the logical true value "true" or the logical false value "false ". For example, three tables: Student (SNO, sname, ssex, sage, sdept) (student ID, name, gender, age, Major) Course (CNO, cname, cpno, ccredit) (course number, course name, elective course number, credits) SC (SNO, CNO, gr

Implement code One, #!/bin/sh # to determine if a file exists # link:www.jb51.net # date:2013/2/28 mypath= '/var/log/httpd/ ' myfile= ' Var/log/httpd/access.log " # Here's the-x parameter to determine if $mypath exists and has executable permissions if [!-X" $myPath "]; then mkdir" $myPath " C10/>fi # Here the-d parameter determines if $mypath exists i

In most cases, you can use test commands to test the conditions. For example, you can compare strings, determine whether a file exists, and whether the file is readable. The following article describes how to use BashShell to check whether a file exists. For more information, see the following. Preface You may often encounter this kind of requirement at work. in the Bash environment of Unix-like systems, h

Tags: inf pointer custom title category same insert common importFor example, there is a query in the Northwind database thatSELECT C.customerid,companyname from Customers CWHERE EXISTS (SELECT OrderID from Orders o WHERE o.customerid=c.customerid)How does this exists work? The subquery returns the OrderID field, but the outside query is looking for the CustomerID and CompanyName fields, and the two fields

The following are some suggestions in theory. The best principle is that on the basis of the above, you can use the execution plan for analysis and get the best statement writing method. The following are some suggestions in theory. The best principle is that on the basis of the above, you can use the execution plan for analysis and get the best statement writing method. 1. Execution Process of EXISTS Select * from t1 where

1. Execution Process of exists Select * from T1 where exists (select null from T2 where Y = X) It can be understood: CopyCode The Code is as follows: for X in (select * from T1) Loop If (exists (select null from T2 where Y = x. x) Then Output the record End if End Loop Performance differences between in and exists:If the subquery results have fewer records, th

Document directory In Exists Differences between in and exists Difference between not in and not exists In In can be divided into three types:I, For example, select * from T1 where F1 in ( apos; A apos;, apos; B apos;) should be more efficient than the following two Select * from T1 where F1 = apos; A apos; or F1 = apos; B apos;Or select * from T1 wh

Shell checks whether a file exists #! /Bin/sh # shell checks whether the directory exists or has the permission mypath = "/var/log/httpd/" myfile = "/var/log/httpd/access. log "# Here, the-x parameter determines whether $ mypath exists and has executable permissions. If [! -X "$ mypath"]; thenmkdir "$ mypath" fi # Here, the-D parameter determines whether $ mypath

SQLServer checks whether the object exists and does not exist. 1 checks whether the database has SQL code ifexists (select * fromsys. databaseswherename 'database name') dropdatabase [database name] ifexists (select * fromsys. databaseswherename 'database name') dropdatabase [database name] 2 SQLServer checks whether the object exists and does not exist. 1 checks whether the database has SQL code if

In Determines whether the given value matches the value in the subquery or list. Exists Specifies a subquery to detect the existence of a row. Use exists andInQuery This example compares two queries with similar semantics. The first query uses exists and the second query usesIn. Note that the two queries return the same information. Use pubs Go Se

1. Shell checks whether a file or directory exists or has permissions 2 .#! /Bin/sh 3. 4. mypath = "/var/log/httpd /" 5. myfile = "/var/log/httpd/access. log" 6. 7. # Here, the-x parameter determines whether $ mypath exists and has executable permissions. 8. If [! -X "$ mypath"]; then 9. mkdir "$ mypath" 10. fi 11. 12. # Here, the-D parameter determines whether $ mypath

Shell command to determine whether a file or folder exists, first look directly at the example: #!/bin/sh #判断文件存在 to determine if the folder testpath= "/volumes/macbookprohd/mr.wen/08 shell command" testfile=/volumes/ macbookprohd/mr.wen/08 shell command/filewen " #判断文件夹是否存在-D if [[!-D" $testPath "]]; then echo" folder does not exist " else echo "folder exists" fi #判断文件夹是否存在 with executable permission

I. Description of exists1.1 The return value of the EXISTS (including not EXISTS) clause is a bool value. There is a subquery inside the exists (SELECT ... From ...), which I call an inner query statement for exist. The inner query statement returns a result set. The EXISTS clause returns a Boolean value based

1 determining whether a database existsif exists(Select * fromsys.databaseswhereName=' database name ')Drop Database [Database name] if exists(Select * fromsys.databaseswhereName=' database name ')Drop Database [Database name]2 Determining whether a table existsif exists(Select * fromsysobjectswhereId= object_idN[Table name]’) and ObjectProperty(ID, N ' isuse

--查看对象是否已经存在 --数据库是否存在 --if exists (select * from sys.databases where name = ’数据库名’) -- drop database [数据库名] if exists(select * from sys.databases where name=‘FGM_POS‘) print ‘存在‘--drop database [数据库名] --表是否存在 --if exists (select * from sysobjects where id = object_id(N’[表名]’) and OBJECTPROPERTY(id, N’IsUserTable’) = 1) -- drop table [表名] if

Shell Determines whether a file exists1. Shell to determine the file, whether the directory exists or has permissions2. #!/bin/sh3.4. Mypath= "/var/log/httpd/"5. Myfile= "/var/log/httpd/access.log"6.7. # the-x parameter here determines whether the $mypath exists and has executable permissions8. If [!-X "$myPath"]; Then9. mkdir "$myPath"Ten. FiOne by one .12. # The-d parameter here determines whether $mypath

Shell determines whether a file existsThe Code is as follows:#! /Bin/sh# Determining whether a file exists# Link: www.jb51.net# Date: 2013/2/28 MyPath = "/var/log/httpd /"MyFile = "/var/log/httpd/access. log" # Here, the-x parameter determines whether $ myPath exists and has executable permissions.If [! -X "$ myPath"]; thenMkdir "$ myPath"Fi# Here, the-d parameter determines whether $ myPath exists.If [! -

= single user; Use sp_dboption to set. Only one user can access the database at a time.32768 = emergency mode.4194304 = autoshrink.1073741824 = cleanly shutdown. You can open multiple locations at the same time. For example, determine whether a database is offline.Select * From master. dbo. sysdatabases where name = 'pubs' and status Check whether the table object exists in SQL Server:Select count (*) from sysobjects where id = object_id ('database