Shulou(Shulou.com)06/01 Report--

Join two tables with no associated fields horizontally. In work, for the display of some reports, you need to show the data in two tables without associated fields, and join horizontally, such as the data of the following two tables:

SELECT * FROM STUDENT T

SELECT * FROM COURSE C

It now needs to be displayed in the style shown in the following figure:

At this time, there are no related fields between the two tables. Left join,right join and full join, which we often use, all need related fields, so we find a field with the same correlation-ROWNUM, which is unique and can be associated, and the problem can be solved by using full-join full join. The SQL statement is as follows:

SELECT A. B.RN, B.*FROM (SELECT S.A., ROWNUM RN FROM STUDENT S) A FULL JOIN (SELECT C. dollars, ROWNUM RN FROM COURSE C) BON A.RN = B.RN

The query results are as follows:

It can be seen that the horizontal join of the two tables can be easily realized through rownum and full join.

If you do not want to display the RN column, do not use * just OK, and display what fields you need:

SELECT A.ID, A.NAME, A.CLASS, B.ID, B.C_NAMEFROM (SELECT S.B., ROWNUM RN FROM STUDENT S) A FULL JOIN (SELECT C.E., ROWNUM RN FROM COURSE C) BON A.RN = B.RN

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