Create view using union all oracle

I would like to create a view with a union of parts of two tables. Hereafter is the statement: create view test AS select ppt. FROM preprocessortransactions ppt union select bm.

Data from two tables into one view - Stack. You can also create an object view or a relational view that supports LOBs, object types, REF data types, nested table, or varray types on top of the existing view mechanism. An object view is a view of a user-defined type, where each row contains objects, each object with a unique object identifier. DML (data manipulation language) statements that contain view references depend on those views, as well as the objects in the view definitions that the views are dependent on. UNION ALL b) use order by select oc, t. If the queries select values of CHAR with different lengths, then the returned value is VARCHARwith the length of the larger CHAR value.

If either or both of the queries select values of datatype VARCHAR then the returned values have datatype VARCHAR2. Full scan using union all inside the view. When a run a query which joins the view with another table, the view is resolved by the optimizer choosing a full scan on the pk instead of doing a unique access.

I have been playing around with hints in order to get the optimizer to chose a unique access but I am not able to do it. Trying to write a view using union statement. As oracle has to create a new table, it must know the column names to be created.

SUBSTR(old_care_lvl,3) cannot be a column name, so you have to use an alias in the query: CREATE TABLE TEST_CARE AS ( SELECT row_i old_care_lvl,SUBSTR(old_care_lvl,3) old_care_lvl,. Oracle Database Forums on Bytes. Just define the CTE first, before the actual UNION query. It does not remove duplicate rows between the various SELECT statements ( all rows are returned).

Views are virtual tables formed by a query. A view is a dictionary object that you can use until you drop it. If a qualified view name is specifie the schema name cannot begin with SYS. A view operates with the privileges of the owner of the view.

Hi, it will be better if we can have the table structure, depending upon what information we have and there is no join condition between different table you could try with UNION. The syntax of a SELECT statement is roughly SELECT Field Field2. I would suggest you get some king of reference on basic SQL. Please do not take this as an offense of any sort - we all had to start somewhere.

If I use a direct sql stmt against the VIEW it works. Schema2: It has the view of the schemaand schemadata’s. As shown in above Schema3: Almost 1million of data’s. The first solution that came to my mind is create view all _time.

For now, I am taking baby steps. Execute each SQL separately and merge and sort the result sets within your program! Sometimes, an external sort may be faster.

To avoid this, you can use the CREATE OR REPLACE clause that preserves the view privileges. Usually, you create a new view based on existing tables. It is different from UNION operator in a way that it does not remove duplicate rows between the various SELECT statements. The WITH CHECK OPTION clause is used for an updatable view to prohibits the changes to the view that would produce rows which are not included in the defining query.

You must have the privileges necessary to create these objects. When you update record(s) in a VIEW , it updates the records in the underlying tables that make up the View. In this step, you create the union query by copying and pasting the SQL statements. On the Create tab, in the Queries group, click Query Design.

Close the Show Table dialog box. On the Design tab, in the Query group, click Union. Access hides the query design window, and shows the SQL view object tab.

MySQL sets a flag, called the view updatability flag, at CREATE VIEW time. The flag is set to YES (true) if UPDATE and DELETE (and similar operations) are legal for the view. Otherwise, the flag is set to NO (false).

The IS_UPDATABLE column in the INFORMATION_SCHEMA. VIEWS table displays the status of this flag.