how to use if else condition in sql query

Case has two formats. Simple case function and case search function.--Simple case function when ' 1 ' then ' Male ' when ' 2 ' then ' women ' else ' other ' end--case search function case when sex = ' 1 ' Then ' man ' when

Job Requirements: Query data according to different conditions, there are drop-down list and radio button twoIf you're just querying for a specific condition, it's simple, just add the appropriate condition after the where condition, like this:

To implement multi-condition query, if the value is 0, it is not limited to any conditions. how can I use SQL? for example, if a certain type of store in a region is not limited to a Chinese query, the where Region value is not required, but only

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

In the past two days, I have provided a query example for a brother I know online. I would like to summarize it more or less and share it with you here. Why is it a combination of multiple conditions? For spatial queries, sometimes the query

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

Header ("Content-type:text/html;charset=utf8");Functions of PHP Operations databasefunction Phpsql ($dbconfig, $type, $field = ", $data =array (), $condition =array (), $join =array ()) {Determine that the database connection host does not existif (!

SQL -- Process Multi-condition query and SQL page query on the page Two methods are used to process multi-condition queries in the past. The first method is to determine the fields to be filled in the condition, and then determine whether the

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,

After several studies have written the following code, there is a need to refer to the following Copy Code code as follows: Kd=server. HTMLEncode (Request ("keyword")) If kd<> "" Then Kd=trim (KD) ' Kd=replace (KD, "", "") Kd=replace (