条件当中含有and,sql语句会通过优化器进行优化 #1.如果有and相连,找到第一个有索引的 并且树的高度最矮的字段进行优化 select count(*) from s1 where email = xboyww1000@oldboy; select count(*) from s1 where email = xboyww1000@oldboy and id=1000; select count(*) from s1 where email = xbo...
In this article, I am going to explain the difference between Inner join and full join with examples. This is one of the very common SQL server interview questions. Here we will be using SQL Server 2017 or you can use SQL Server 2008 or above. Read my previous Joins in SQL Server 2017...
But before, let's have look into the basics of views and materialized view individually for better understanding of the differences between them. Views in SQL Views are the logical and virtual copy of a table that is created by executing a "SELECT query" statement. The views are not stored...
The INNER JOIN between two tables returns all the rows which are present in both the tables. The concept of JOIN in SQL can be visualized using Venn diagrams. In the below Venn diagram, the circles represent the tables, and the intersection between those circles represents the INNER JOIN’s...
Data Type: Consider the data type of the variable or field. Some programming languages differentiate between null and blank values based on the data type. For example, in languages like Java, null is used for reference types, while blank can be used for primitive types. ...
Difference Between Inner Join and Outer JoinS.No.Inner JoinOuter Join 1 It returns the record that has a matching value in both tables. It returns the record that has matching value as well as some dissimilar data from the tables. 2 Types of Inner Join - Condition Join, Equi Join and ...
In this article, I am going to explain what is the difference between Inner join and Left join with examples. This is one of the very common SQL server interview questions. Here we will be using SQL Server 2017 or you can use SQL Server 2008 or above. Read my previous Joins in SQL...
Applying WHERE clause on Text values:For applying WHERE clause on text values we generally use like operator. In the above scenario, if we want to find the employees with A in their name, we can write the below SQL query using the “Like” operator condition for the WHERE clause. ...
Break and continue are control flow statements used in looping statements like ‘for’, ‘while’, or ‘do-while’ to alter the flow of execution of a loop inside a program. These statements are also known as jump statements, as they are used to jump in and out of the loop. Break:...
In SQL Server, both the SEQUENCE object and IDENTITY property are used to generate a sequence of numeric values in an ascending order. However, there are several differences between the IDENTITY property and SEQUENCE object. In this article, we will look at these differences. Difference 1: The...