Can we use join for two different database tables?
2 Answers. SQL Server allows you to join tables from different databases as long as those databases are on the same server. The join syntax is the same; the only difference is that you must fully specify table names.
How do you link tables in SQL?
To link to the data, open the destination database. On the External Data tab, in the Import & Link group, click ODBC Database. Click Link to the data source by creating a linked table, and then click OK. In the Select Data Source dialog box, click the .
Can we join two tables without any relation?
The answer to this question is yes, you can join two unrelated tables in SQL, and in fact, there are multiple ways to do this, particularly in the Microsoft SQL Server database. The most common way to join two unrelated tables is by using CROSS join, which produces a cartesian product of two tables.
What happens when you join two tables together without an on clause?
Any JOIN without an ON clause is a CROSS JOIN. The LEFT JOIN is an outer join, which produces a result set with all rows from the table on the “left” (t1); the values for the columns in the other table (t2) depend on whether or not a match was found. JOINs can be concatenated to read results from three or more tables.
How do I join two tables in SQL without joins?
One way to join two tables without a common column is to use an obsolete syntax for joining tables. With this syntax, we simply list the tables that we want to join in the FROM clause then use a WHERE clause to add joining conditions if necessary.
Can we join two tables without primary key?
Table1: Order; Column Name: Id (PK), SecurutyId, UserId. ** But no foreign key in this table. Table2: Security; Column Name: Id (PK), SecurutyId (FK), Symbol.
How do you join two tables without common fields?
3 Answers
- We can use the Cartesian product, union, and cross-product to join two tables without a common column.
- Cartesian product means it matches all the rows of table A with all the rows of table B.
- Union returns the combination of result sets of all the SELECT statements.
What is required to join two tables in SQL?
To apply join between two tables, one table must contain a column that is a reference for the other table. In the example above, the Employees table must have a column that contain a reference key for the department (ex: Department id).
How do I join the same table in SQL?
To construct a self join, you select from the same table twice by using the SELECT statement with an inner join or outer join clause. Because you refer to the same table twice in the same statement, you have to use table aliases.
How do you join two columns?
To join two columns Drag a column from one object to a column in a second object that you want to join. Toad draws a line between the tables with an arrow in the direction of the join. To visualize how values (rows) are distributed within the joined tables, you can analyze the join.
Can I join a table with itself in SQL Server?
SQL Server self join syntax. A self join allows you to join a table to itself. It is useful for querying hierarchical data or comparing rows within the same table. A self join uses the inner join or left join clause. Because the query that uses self join references the same table, the table alias is used to assign different names to the same table within the query.
Where clause in Join SQL?
SQL Joins are used to relate information in different tables. A Join condition is a part of the sql query that retrieves rows from two or more tables. A SQL Join condition is used in the SQL WHERE Clause of select, update, delete statements.