Create an index using SQL

Create an index using SQL to create an index for a table, start the ISQLw program in the SQLSever Program Group on the taskbar. In the query window, enter the following statement: CREATEINDEXmycolumn_indexONmytable (myclumn) to create an index named mycolumn_index. You can give an index any name, but you should

Create an index using SQL to create an index for a table, start the ISQL/w program in the SQL server program group on the taskbar. In the query window, enter the following statement: create index mycolumn_index ON mytable (myclumn) to CREATE an INDEX named mycolumn_index. You can give an index any name, but you should

Create an index using SQL
To create an index for a table, start the ISQL/w program in the SQL server program group on the taskbar. Enter the query window and enter the following statement:

Create index mycolumn_index ON mytable (myclumn)

This statement creates an index named mycolumn_index. You can give an index any name, but you should include the field name of the index in the index name, which is helpful for you to figure out the intention of creating the index in the future.
Note:
After the command is executed, the following information is received:
This command did not return data, and it did not return any rows
This indicates that the statement is successfully executed.
Index mycolumn_index to the mycolumn field of the table mytable. This is a non-clustered index and a non-unique index. (This is the default attribute of an index)
If you want to change the index type, you must delete the original index and recreate it. After an index is created, you can use the following SQL statement to delete it:

Drop index mytable. mycolumn_index

Note that you must include the table name in the drop index statement. In this example, the index you deleted is mycolumn_index, which is the index of mytable.
To create a CLUSTERED index, you can use the keyword CLUSTERED. Remember that a table can only have one clustered index.
Here is an example of how to create a clustered index for a table:

Create clustered index mycolumn_clust_index ON mytable (mycolumn)

If the table contains duplicate records, an error occurs when you try to use this statement to create an index. However, you can create indexes for tables with duplicate records. You only need to use the keyword ALLOW_DUP_ROW to tell SQL Sever:

Create clustered index mycolumn_cindex ON mytable (mycolumn) WITH ALLOW_DUP_ROW

This statement creates a clustered index that allows Repeated Records. You should try to avoid repeated records in a table. However, if the record already appears, you can use this method.
To create a UNIQUE index for a table, you can use the keyword UNIQUE. This keyword can be used for clustered indexes and non-clustered indexes. Here is an example:

Create unique coustered index myclumn_cindex ON mytable (mycolumn)

This is the index creation statement that you will frequently use. Whenever possible, you should try to create a unique clustered index for a table to enhance query operations.
Finally, you need to create an index for multiple fields -- composite index -- the index creation statement contains multiple field names at the same time. The following example creates an index for the firstname and lastname fields:

Create index name_index ON username (firstname, lastname)

In this example, a single index is created for two fields. In a composite index, You Can index up to 16 fields.

-- Join
SELECT
FROM dbo. k_baoming INNER JOIN
Dbo. k_kebiao ON dbo. k_baoming.o_flowid = dbo. k_kebiao.f_apply_id

-- Left Outer Join
SELECT dbo. k_baoming.o_flowid
FROM dbo. k_baoming LEFT OUTER JOIN
Dbo. k_kebiao ON dbo. k_baoming.o_flowid = dbo. k_kebiao.f_kebiaoID

-- Right Outer Join
SELECT dbo. k_baoming.o_flowid
FROM dbo. k_baoming RIGHT OUTER JOIN
Dbo. k_kebiao ON dbo. k_baoming.o_flowid = dbo. k_kebiao.f_kebiaoID

-- Complete External Connection
SELECT dbo. k_baoming.o_flowid
FROM dbo. k_baoming FULL OUTER JOIN
Dbo. k_kebiao ON dbo. k_baoming.o_flowid = dbo. k_kebiao.f_kebiaoID

-- Do not use OUTER