if else statement in sql query example

MS SQL Server Query optimization methodThere are many reasons for the slow speed of queries, which are common1, no indexes, or no indexes (this is the most common problem with query slowness, is the flaw in programming)2, I/o throughput is small,

SQL statement case when then else end returns a qualified value, sqlcase Case has two formats Simple Case functions and Case search functions: -- Simple Case function CASE sex WHEN '1' then' male 'when' 2' then' female 'else' other 'ends -- Case

Case has two formats. Simple case function and case search function.--Simple Case functionCase SexWhen ' 1 ' Then ' men 'When ' 2 ' then ' women 'Else ' other ' END--case search functioncase If sex = ' 1 ' Then ' man 'When sex = ' 2 ' Then ' women

Case has two formats. Simple case function and case search function.--Simple Case functionCase SexWhen ' 1 ' Then ' men 'When ' 2 ' then ' women 'Else ' other ' END--case search functioncase If sex = ' 1 ' Then ' man 'When sex = ' 2 ' Then ' women

Cause Analysis and Solution of slow SQL query speed, and cause analysis of slow SQL query speed Cause Analysis and Solution for slow SQL query speed There are many reasons for slow query speed. The following are common causes:　　1. No index or no

Next: T-SQL Dynamic Query (3)--Static SQLObjective:There's a lot of talk about dynamic queries, and this article describes some of the ways to use dynamic SQL to solve dynamic queries.Why use Dynamic sql:In many projects, dynamic SQL is widely used

https://blogs.msdn.microsoft.com/apgcdsd/2011/01/10/sql-1/First, IntroductionA problem that is highlighted in front of many developers or database administrators is the performance of the database system. The performance of the system is not ideal

The following statements in the complete SQL operation are Mssql statements and cannot be used in access. The following statements in the complete SQL operation are Mssql statements and cannot be used in access. SQL classification: DDL-Data

MySQL is the most basic SQL syntax. For more information, see. The most basic SQL syntax/Statement of MySQL. For more information, see. DDL-Data Definition Language (Create, Alter, Drop, DECLARE) DML-data manipulation language (Select, Delete,

1. Single-Table query: Filter the records in the table according to where conditions, form an intermediate table (this intermediate table is not visible to the user), and then select the corresponding column according to the Select column of select