mysql-views View

Views: A non-real-world table that contains complex queries can also be understood as a result of a query.

Add a concept: Temporal table Query (subquery): Is to nest a query again in the query statement, and set the nested query alias

SELECT    *     from     (SELECT   nid, NAME from      tb1        WHERE    >2as AWHERE     > ' Alex ';

1. Create a view:

1 -- format: CREATE view name  as SQL statement 2CREATEVIEWas3 selet nid,  name   from   A4 WHERE  > 4

2. Delete the view:

1 -- format: DROP view name 2 DROP VIEW v1

3. Modify the View:

1 --format: ALTER view name as SQL statement2 ALTER VIEWV1 as3Selet A.nid, B. NAME fromA4  Left JOINB ona.ID=B.nid5  Left JOINC ona.ID=C.nid6 WHEREa.ID> 2  andC.nid< 5

4. Use the view: Query the view as a table

Select *  from V1

mysql-views View