oracle sql not null

deptno=10 or deptno=50 or deptno=null, because is or connected, so long as one condition is true, the whole is fed to true. So Deptno's record for 10 shows up.Sql> Select Deptno2 from Dept3 where Deptno not in (10,50,null);Here is equivalent to where not (deptno=10 or deptno=50 or deptno=null), take the deptno=20 record for example.Not (20=10 or 20=50 or 20=

Directory===============================================1. The arrangement with null value2.top/bottom N Query3.first/last ranking Query4. Query by LevelOne, with a null value of the arrangement:In the previous article on Oracle development topics: Analytic functions 2 (Rank, Dense_rank, row_number), we have learned how to arrange and group records in a full arra

Recently, writing Oracle stored procedures is different from SQL. in SQL, select statements can return result sets. in Oracle statements, pointers (cursors) are used to write SQL statements, a little uncomfortable. yesterday, I wrote a test stored procedure. The stored proce

Tags: style color io strong data for AR CTIAdding a NOT null field before 11g is very slow, very fast after 11g, let's do a test first and then explore the principle.Sql> select * from V$version;BANNER----------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.2.0.1.0-64biPL/SQL Release 10.2.0.1.0-productionCO

I had trouble with my Oracle stored procedures for more than a month. Due to different versions, I spent a whole day today and finally solved them later in the afternoon, this problem accounts for 10% of the performance appraisal this month. It is very important to write down the question and give a brief explanation to everyone. This is the case. Some time ago, a company's management information system was about to launch a press conference. In terms

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 varchar2 (10): =

Insert into Table (TestCol) VALUES ('')The TestCol field has been designed as not null during design, but we need to know that in SQL server, null and space are different, that is, the preceding statement inserts an empty field, but is not NULL. It is considered to be a violation of non-

Insert into table (testcol) values ('') The testcol field has been designed as not null during design, but we need to know that in SQL Server, null and space are different, that is, the preceding statement inserts an empty field, but is not null. It is considered to be a violation of non-

Oracle uses orderby to sort null values. When order by is used in Oracle for query and sorting, if there is a null value in the sorting field, the sorting result may not reach the expected result. For example: [SQL] view plain copy Select * from test order by age desc;

Recent. In the development, write the time encountered some problems, find a long time to find the reason. And it was never known.So write it down here and give it to yourself and everyone.one, null valueHere's an example of the simplest sample. Ordinary work is certainly more complex than this SQL, in this is just to put this error point presented, he may be a complex