sql compare strings not equal

Pl/SQL is an extension of oracle's standard database language. oracle has integrated pl/SQL into oracle servers and other tools, in recent years, more developers and DBAs have started to use pl/SQL. This article describes basic pl/SQL syntax,

SQL statement optimization improves database performance and SQL statement database performance In systems with unsatisfactory performance, apart from the fact that the application load exceeds the server's actual processing capacity, it is more

From: http://blog.csdn.net/zhiguo2010/article/details/5737492 In Oracle, the Null String is considered null, and any value compared with null is null. In this way, an exception occurs when comparing two strings. See the following example: DeclareI

Http://www.cnblogs.com/happycat1988/p/4779805.htmlRecently found when comparing strings in SQL Server if the end of the string is a space then SQL Server ignores those spaces and compares them directly to the usual string judgment logic in the

Single-record functions in SQL 1. ASCIIReturns the decimal number corresponding to the specified character; SQL> select ASCII ('A') A, ASCII ('A') A, ASCII ('0') zero, ASCII ('') space from dual; A A zero space ------------------------------------ 65

To put it simply, the use of strings is mainly divided into two steps.(1) Define and initialize the string.(2) Use a string to perform some processing on the string.You have already learned how to create a string, as shown below.Create a String

PHP can process strings in a variety of ways, but sometimes you need to select the simplest and ideal solution. This article lists 10 common cases of string processing in PHP and provides the most ideal processing method. 1. determining the length

PHP can process strings in a variety of ways, but sometimes you need to select the simplest and ideal solution. This article lists 10 common cases of string processing in PHP and provides the most ideal processing method. 1. PHP for determining a

SQL optimization should be adjusted from five aspects:1. Remove unnecessary full table scans for large tables2. cache full table scan for small tables3. Verify the use of optimized Indexes4. Verify the optimized Connection Technology5. minimize the

Data Control Language DCL) Data Control Language (DCL) is a statement used to set or change database user or role permissions. These statements include GRANT, DENY, REVOKE, and other statements. By default, only members of sysadmin, dbcreator,