Category：MsSql
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Time：2021-5-12
We all know that the aggregate function count() can count the number of rows in a table. If you need to count the number of rows of each table in the database (DBA may have this requirement), you must generate a dynamic SQL statement for each table and execute it with count() function to get […]
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Time：2021-5-11
preface In the development, the query function runs through the full text. We use stored procedure paging query one by one, and support dynamic splicing where condition. Key points:Support dynamic splicing where condition Students who have questions about the use of stored procedures【Creation and use of SQL server stored procedure】Make up lessons. As for whether […]
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Time：2021-5-11
1、 Define table variables Copy codeThe code is as follows: DECLARE @T1 table ( UserID int , UserName nvarchar(50), CityName nvarchar(50) ); Insert into @ T1 (user ID, user name, city name) values (1, ‘a’,’shanghai ‘)Insert into @ T1 (user ID, user name, city name) values (2, ‘B’,’Beijing ‘)Insert into @ T1 (user ID, user […]
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Time：2021-5-10
In SQL server, count (*) or count (1) or count ([column]) is probably the most commonly used aggregate function. In fact, many people can’t distinguish the three. This article will elaborate the function, relationship and the underlying principle of the three. Usually, I often see some so-called optimization suggestions that use count (1) instead of […]
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Time：2021-5-9
Sometimes it is necessary to export the data in SQL server to other departments at one time for correlation or analysis. Of course, this requirement is very simple for SSIS, but it is a big deal to establish a SSIS package just by exporting the data at one time. There are many bugs in the […]
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Time：2021-5-8
catalogue preface Installation of virtual machine Commands and operations Basic command syntax Case sensitive SQL keyword and function name Column and Index Names alias Too long to see? Space Database connection Connection of SSMS Connection of command line Database operation establish delete constraint integrity constraint Common constraints NOT NULL UNIQUE PRIMARY KEY FOREIGN KEY DEFAULT […]
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Time：2021-5-8
Table valued function SQL server provides functions similar to other programming languages, and the essence of functions is usually encapsulation of a piece of code and return value. In SQL server, functions can return not only simple data types (int, varchar, etc.), but also a set, that is, a table. According to whether to […]
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Time：2021-5-7
The paging stored procedure of SQL Server 2005 is divided into three versions, one is not optimized, the other is optimized, and the last one supports join. The paging stored procedure of SQL Server 2000 can also run on SQL Server 2005, but its performance is not as good as that of SQL Server 2005. […]
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Time：2021-5-6
As mentioned in the above article, win’s performance monitor is a necessary tool for monitoring database performance. Next, I will introduce some common monitoring indicators to you. In fact, they are nothing more than the operation indicators of disk, CPU, memory and other hardware, as well as the database’s own locks, user connections, and other […]
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Time：2021-5-5
Recently, when struggling with azure SQL database, we found a new Microsoft database management tool: azure Data Studio. From the name, azure Data Studio seems to be specially developed for azure, but it is not. It also supports the query and management of traditional SQL server.Azure Data Studio is a cross platform database management tool, […]
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Time：2021-5-5
1. Use SQL server for maintenance plan I won’t show you the screenshot here. This is relatively simple. It’s nothing more than dragging two “backup database” tasks and one “clear maintenance” task through SQL Server’s own maintenance plan. Points to be noted: 1) In the backup task, select “all user databases” as far as possible, […]
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Time：2021-5-4
Table structure Experiment content 1 Create a database cap with SQL statements. The data file name is capdata.mdf. The initial storage space of the data file is 50m, the maximum storage space is 500m, and the automatic growth of the storage space is 10m. CREATE DATABASE CAP ON ( NAME = CAP, File name =’c:: […]
