coalesce sql

This article is a record of the programmer's SQL code, and this time it will cover other functions commonly used by SQL Server. (Other database is not listed here, want to see more attention to the "Programmer's SQL Code"). Other functions include: type conversion functions, null value processing functions, Process Control functions,

Sqlserver supports locating the current page and customizing sorted paging SQL statements (rejecting dynamic SQL statements) Sqlserver supports locating the current page and customizing sorted paging SQL statements (rejecting dynamic SQL statements) 1. Scenario: query by student ID and return all students in the stude

Select COUNT (VIRTUALACC) into V_count from t_atmmonitor WHERE VIRTUALACC = v_number;For the stored procedure, the value of the count (VIRTUALACC) statistic is assigned to the variable v_count, and the V_count variable is called in subsequent stored procedures.In the SQL statementSelect into from and insert into select differGrammar:Insert into table2 (field1,field2, ... ) Select Value1,value2, ... From table1Requirements table2 must existThe differen

---- Set a non-primary key to clustered index [Step 4] to: http://king123654789.iteye.com/blog/1169191 1. View All indexes. Clustered indexes are created on the primary key by default.Sp_helpindex person 2. -- delete the primary key constraint and remove the index constraint on the primary key queried in [1], for example, PK _ person _ 117F9D94. Remove the primary key constraint from the primary key field. This field is not the primary key.Alter table person drop constraint PK _ person _ 117F9

* (Unitsinstock+unitsonorder) from Products In the example above, if there is a "unitsonorder" value of NULL, then the result is null. Microsoft's ISNULL () function is used to specify how NULL values are handled. NVL (), Ifnull (), and coalesce () functions can also achieve the same result. Here, we want the NULL value to be 0. The following, if "UnitsOnOrder" is null, is not conducive to the calculation, so if the value is null then ISNULL () retu

Transaction Processing Mechanism in SQL sp_lock2Version: SQLServer7.02000Createdby: Alexander chigrikwww.mssqlcity.com Transaction Processing Mechanism in SQL sp_lock2Version: SQL Server 7.0/2000 Created by: Alexander Chigrikhttp: // www.MSSQLCity.com/-all about ms SQL (SQL

Artificial Intelligence automatic SQL optimization tools-SQLTuning for SQL Server, SQL-sqltuning In response to this situation, the artificial intelligence automatic SQL optimization tool came into being. Now I will introduce this tool: SQLTuning for SQL Server. 1.

First of all, the so-called SQL dynamic and static, refers to when SQL statements are compiled and executed, both are used in SQL embedded programming, which is referred to as embedded refers to the SQL statement embedded in the high-level language, rather than the type of microcontroller embedded programming.In a high

Tags: style blog http color using strongSum is the standard SUM function in an SQL statement, and the SUM function returns null if there are no records that match the criteria.But in most cases, we want it to return 0 instead of NULL if the condition record is not met, so we can use the following method, for example:SELECT COALESCE (SUM (name), 0) from the person WHERE ID > 0Okay, so you don't have to bothe

: COALESCE (Expression,value1,value2......,valuen)Instance:Select F_name,f_csrq,coalesce (F_CSRQ, ' 2015-10-10 ') as an important periodFrom t_studentarchives where f_name = ' 11 '(if F_CSRQ is null, the important period is 2015-10-10; otherwise, the important period is F_CSRQ)Select F_name,f_csrq,f_zz,coalesce (f_csrq,f_zz, ' 2015-10-10 ')As important period fro