Comparison of data in Oracle database tables

Is the structure of the two tables the same, you give the structure of the table, and give it the fields that need to be compared.

t1 is the complete table.

t2 is a small data table.

Needs to be updated.

select ,,a,china_other, from t1 a,t2 b

whereand and =

and (

or <>

or <>

or <>

Need to add.

select * from t1 a

where noexists

select 1 from t2 b

where = )

EST Table: <>

test1 table:

Now to find out the difference between the two tables, you need to use the method of minus and union to find out, and the statement is as follows:

select t1.* from(select * from testminusselect * pins from test1) t1union select t2* from(select * from test1minusselect * from test) 1

select t1.* from

select * from test

minusselect * from test1) t1<>

unionselect t2.* from

select * from test1

minusselect * from test) t2;

select t1.* from

select * from test

minusselect * from test1) t1union

select t2.* from

select * from test1

minusselect * from test) t2;

The data of the Burning Mountain Tour in the red box is the content with differences.

EST Table: <>

test1 table:

Now to find out the difference between the two tables, you need to use minus and union to find out the data, and the statement is as follows:

select t1.* from(select * from testminusselect * from test1) t1union select t2.* from(select * from test1minusselect * from test) 1

select t1.* from

select * from test

minusunion

select t2.* from

select * from test1

minusselect * from test) t2;

select t1.* from

select * from test

minusselect * from test1) t1union

select t2.* from

select * from test1

minusselect * from test) t2;

The data in the red box is the content with discrepancies.

If you have two tables with the same table structure:

test table:

test1 table:

Now to find out the difference between the two tables, you need to use minus and union to find out the data, and the statement is as follows:

select t1.* from

select * from test

minusselect * from test1) t1union

select t2.* from

select * from test1

minusselect * from test) t2;The query result is as follows, and the data in the red box is the content with differences.

select * from a minus select * from b;

select * from b minus select * from a;

Compare the differences between two tables with the same table structure using minus. Hope it helps.

After understanding the Oracle database, it is necessary to compare Oracle with Sybase SQL Server, Oracle uses a parallel server model, while Sybase SQL Server uses a virtual server model, which does not decompose a query into multiple subqueries and then execute these subqueries on different CPUs at the same time. We can say that Oracle outperforms Sybase in terms of symmetric multiprocessing. If the number of databases reaches more than GB, we can start from two aspects in improving the performance of the system, one is to improve the performance of a single server, and the other is to increase the number of servers.

Based on this, if we are looking to improve the performance of a single server, Oracle Database is a better choice because they provide parallelism on a symmetrical multi-CPU system. On the contrary, since Sybase's navigation server enables all users on the network to register with the navigation server and make data access requests through the navigation service, the navigation server breaks down the user's request and then automatically directs it to multiple SQL servers controlled by it, thus providing parallel processing capabilities on the basis of decentralized data, we can choose it. These are compared under the same conditions and circumstances so that they are comparable.

In terms of data distribution and update, Oracle uses an automatic server-based 2PC (two-stage submission), while Sybase uses a programmable 2PC based on client db-library or ct-library, so we must choose the database according to the need, for example, the development of social insurance software, considering the large amount of data, more concurrent operations, and high real-time requirements, Our backend is basically an oracle database. An oracle server consists of an oracle database and an oracle instance. An oracle instance consists of a system global memory structure and a background process that is used by the finger to manage the database.

select * from a minus select * from b;

select * from b minus select * from a;

Compare the differences between the two brothers with the same structure as the Chong Ling table with the envy of the relatives minus. I hope it will be helpful to you. Hope.

EST Table: <>

test1 table:

Now to find out the difference between the two tables, you need to use the method of minus and union to find out, and the statement is as follows:

select t1.* from(select * from testminusselect * pins from test1) t1union select t2* from(select * from test1minusselect * from test) 1

select t1.* from

select * from test

minusselect * from test1) t1<>

unionselect t2.* from

select * from test1

minusselect * from test) t2;

select t1.* from

select * from test

minusselect * from test1) t1union

select t2.* from

select * from test1

minusselect * from test) t2;

The data of the Burning Mountain Tour in the red box is the content with differences.