How SQL practices string concatenation 10

Add a field in Table 1 as a foreign key and Billno in Table 2

This is achieved through query statements.

1. Custom functions.

2. Use the SQL of the Connect By substatement to connect the SQL with the sys connect by path function.

3. Custom aggregate functions.

How to use SQL Server log clearing.

1. Set the database mode to simple mode: open SQL Enterprise Manager, click Microsoft SQL Server in the root directory of the console -- > SQL Server group -- > double-click to open your server -- > double-click to open the database directory -- > select your database name (such as forum database forum) -- then right-click to select properties -- > select options -- > select "Simple" in the mode of failure restore, and then press OK to save.

2. Right-click on the current database to see the shrink database in all tasks, generally the default settings in it do not need to be adjusted, just click to confirm.

3. After the database is shrunk, it is recommended to set your database properties to standard mode again, and the operation method is the same as the first point, because logs are often an important basis for recovering the database in some abnormal cases.

You can use the stuff function in conjunction with xml path(), e.g. select stuff(

select ','+convert(varchar, from as sv where sv.[type]='p' and <10 for xml path(''),1,1,'')

The result is: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

You mean a separate column of data, and then put together a row of data, right? For example, there are three rows in a column, which are "heaven", "earth" and "man". You want to get a line of data "heaven, earth and people" now, this is what it means.

Then the method is for xml path, the specific way to write according to the actual situation, here can only say that using this method, how to write it should be written according to your field.

Column splicing, stuff for xml path() method, you can look it up, this talks a lot, you can customize the middle spacer, the above example is one of them.