t sql fundamentals

Ref: http://blogs.lessthandot.com/index.php/DataMgmt/DataDesign/sql-server-precision-and-scale-problems SQL Server precision and scale problemsby George mastros 24 Nov 2008,Categories:Data Modelling design, Microsoft SQL Server Specified people are confused about SQL Server's precision and scale. this is unfortu

1. What is SQL injectionSQL injection, by inserting a SQL command into a Web form to submit or entering a query string for a domain name or page request, eventually achieves a malicious SQL command that deceives the server.2. How to prevent SQL injectionThere are two ways to prevent

ObjectiveFor a long time did not write a blog, people become lazy a lot, should say originally also not very diligent. But today for this tool, you have to be diligent, there really is no free lunch.The Query Designer and Toad for Oracle, which used SQL Server 2000 before, have the ability to format SQL statements, which is very handy, especially for those of me with mild obsessive-compulsive disorder. When

Dynamic Content Summary: In the Pl/sql development process, the use of sql,pl/sql can achieve most of the requirements, but in some special cases, the use of standard SQL statements or DML statements in Pl/sql can not achieve their own needs, For example, the need to dynamic

Use Oracle SQL * Plus to analyze SQL I. Analyze and execute SQL statements SQL> set autotrace on; Description: Enables automatic analysis statistics and displays the running results of SQL statements. SQL> set autotrace traceonly;

ERROR 1418 (HY000): This function has none of DETERMINISTIC, no SQL, or reads SQL DATA..., hy000deterministic Create function today CREATE FUNCTION `func_get_split_string_total`(f_string varchar(1000),f_delimiter varchar(5)) RETURNS int(11)BEGIN return 1+(length(f_string) - length(replace(f_string,f_delimiter,'')));END Error message: ERROR 1418 (HY000): This function has none of DETERMINISTIC, no

in 10g, Oracle launched its own SQL optimization aids : SQL Optimizer (SQL Tuning Advisor :STA) , it is the new Dbms_sqltune package. Use the STA to make sure that the optimizer is in CBO mode. but I think that using this tool is only suitable for people who don't understand SQL at all, and don't think that tools can

Tags: show change useful stage Auth tab ros. SQL descriptionby Don Kiely, 2014/06/04 reprinted from: http://www.sqlservercentral.com/articles/Stairway+Series/109941/ This series This article was part of the stairway Series:stairway to SQL Server Security Relational databases are used in a wide variety of applications, through a widely distributed network, especially the Internet, from dazzling client connec

SQL Server paging query processing method summary, SQL Server Paging Sqlserver2008 does not support the keyword limit, so its paging SQL query statement cannot be performed using MySQL. Fortunately, sqlserver2008 provides top, rownumber, and other keywords, in this way, you can use these keywords to implement paging. Below are some query scripts I have found on t

Introduction Sp_who2 is a well known utility that shows what spids are currently executing. however the information it shows is relatively limited. for example, it only shows the type of command executing as select, delete etc, with no reference to the actual underlying SQL executing. Knowing what SQL is executing can be vital in debugging why a query is taking a long time, or determining if it is being blo

1. Meaning of withThe with as phrase, also known as subquery factoring, allows you to do a lot of things and define an SQL segment, which will be used by the entire SQL statement. Sometimes, it is to make the SQL statement more readable, or it may be in different parts of Union all, as part of the provided data.Especially useful for Union all. Because each part o

In the development of Oracle When 9i is used, the database still uses the ansl SQL/92 standard link syntax. We recommend that you use the SQL/92 standard syntax when using Oracle 9i and later; the standard SQL/86 syntax should be used when Oracle 8i and earlier are used. ----- Oracle Database 10g SQL Development Guide

are not saved, and recursive queries can be implemented.Third, Embedded SQLHow do I use SQL in a programming language?The main problem is to solve the following problems: How to make the programming language accept SQL statements; How to get programs and databases to exchange messages and data; The query result is a collection, how to pass it to the variables in the programming language;