How do I join two tables with the same column names in SQL?

How do I join two tables with the same column names in SQL?

In a natural join, all the source table columns that have the same name are compared with each other for equality. With the column-name join, you select which same-name columns to compare. You can choose them all if you want, making the column-name join (effectively) a natural join.

What do we do when a column name is same in both the tables joined?

When two tables use the same column name(s), use table_name. column_name or table_alias. column_name format in SELECT clause to differentiate them in the result set. Use INNER JOIN whenever possible because OUTER JOIN uses a lot more system resources and is much more slower.

Can two tables have same column name?

Column names have to be unique, but only within the context of the table that contains the columns. Table names have to be unique, but only within the context of the schema that contains the tables, etc.

How do I fix ambiguous column name in SQL inner join?

One of the simplest ways to solve an “ambiguous name column” error — without changing column name — is to give the tables you want to join an alias. This sends a clear information to the SQL Machine the columns are different.

What is an equi join in SQL?

An equi join is a type of join that combines tables based on matching values in specified columns. Please remember that: The column names do not need to be the same. The resultant table contains repeated columns. It is possible to perform an equi join on more than two tables.

Which join is based on all columns in the two tables that have the same?

A NATURAL JOIN is a JOIN operation that creates an implicit join clause for you based on the common columns in the two tables being joined. Common columns are columns that have the same name in both tables.

How do I join two tables in SQL without duplicates?


  1. Merge into (in SQL), but ignore the duplicates.
  2. Using UNION to combine same SQL Tables and searching for a specific word return duplicate rows.
  3. Copy data from one table to another without creating duplicate records SQL.
  4. Join 2 tables in SQL without duplicates.

How do I SELECT the same column from multiple tables in SQL?

Example syntax to select from multiple tables:

  1. SELECT p. p_id, p. cus_id, p. p_name, c1. name1, c2. name2.
  2. FROM product AS p.
  3. LEFT JOIN customer1 AS c1.
  4. ON p. cus_id=c1. cus_id.
  5. LEFT JOIN customer2 AS c2.
  6. ON p. cus_id = c2. cus_id.

Can SQL tables have the same name?

Within a database, base tables and views share the same namespace, so a base table and a view cannot have the same name.

Can we create two columns with same name in a relational table?

You cannot create two columns with exactly the same name.

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