How does Oracle define the columns of a result set?

2 years ago
Isabella Edwards
1 minute

In Oracle, you can use the SELECT statement to specify the columns in the result set. Here are some common methods:

  1. Specify column names: You can use column names in the SELECT statement to specify which columns to return in the result set. For example:
SELECT column1, column2, column3
FROM table_name;

This will return the values of columns 1, 2, and 3 in the table.

  1. Wildcard can be used to select all columns. For example:
SELECT *
FROM table_name;

This will return all columns in the table.

  1. In SELECT statements, expressions can be used to calculate new columns. For example:
SELECT column1, column2, column1 + column2 AS sum
FROM table_name;

This will return column1, column2, and their sum as columns in the result set.

  1. Use aliases: You can use the AS keyword to assign an alias to a column. For example:
SELECT column1 AS alias1, column2 AS alias2
FROM table_name;

This will return columns named alias1 and alias2.

It is important to note that the order of the columns will be returned according to the order in the SELECT statement, and can be sorted as needed.

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