What does SELECT 1 from dual do?

Question

In your case, SELECT 1 FROM DUAL; will simply returns 1 . You need it because the INSERT ALL syntax demands a SELECT clause but you are not querying the input values from a table. Dual is not a temporary table. 13 мар. 2013 г.

What is the use of select 1 from dual?

When you select an expression say 1 from a table (can be dual or any other table), it will return the expression depending on the number of rows in the table. Eg:- Select 1 from dual; returns 1 as there is only one record in dual.

What does select 1 from do?

The statement 'select 1' from any table name means that it returns only 1. For example, If any table has 4 records then it will return 1 four times.

What is select * from dual in Oracle?

Selecting from the DUAL Table: DUAL is a table automatically created by Oracle Database along with the data dictionary. DUAL is in the schema of the user SYS but is accessible by the name DUAL to all users. It has one column, DUMMY , defined to be VARCHAR2(1) , and contains one row with a value X .

What is the difference between select 1 and select *?

Hi, Select * from any table will fetch and display all the column in that table, while Select 1 from any table will display one row with 1 without any column name.

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