Frequent question: What is the difference between select and select * in SQL?

SELECT * will return 100 columns * 10 bytes worth of data while SELECT ColA, ColB, ColC will return 3 columns * 10 bytes worth of data. This is a huge size difference in the amount of data that is being passed back across the wire.

What is the difference between select and select *?

There is no semantic difference between SELECT , select and SeLeCt .

What does select * Mean SQL?

An asterisk (” * “) can be used to specify that the query should return all columns of the queried tables. SELECT is the most complex statement in SQL, with optional keywords and clauses that include: The FROM clause, which indicates the table(s) to retrieve data from.

What is the difference between select * and select column name?

select * will give additional column (which you’ve just added to the table) and application will get additional column and may raise error. From a perf perspective, then are the same (if you list all columns).

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Should you use select * in SQL?

That’s all about why you should not use SELECT * in SQL query anymore. It’s always better to use the explicit column list in the SELECT query than a * (star) wildcard. It not only improves the performance but also makes your code more explicit.

What does SELECT 1 means in SQL?

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 the difference between the SELECT statement to SELECT distinct?

It’s the same as select distinct col1, col2, .. for all columns in the table: the resulting columns returned will also be different accordingly. That is, the * with distinct is effectively the same difference as select id vs select * .. if you have only Id column in your table then there is no difference.

Why * is used in SQL?

The second part of a SQL query is the name of the column you want to retrieve for each record you are getting. You can obviously retrieve multiple columns for each record, and (only if you want to retrieve all the columns) you can replace the list of them with * , which means “all columns”.

What is * called in SQL?

Queries. … An asterisk (” * “) can be used to specify that the query should return all columns of the queried tables. SELECT is the most complex statement in SQL, with optional keywords and clauses that include: The FROM clause, which indicates the table(s) to retrieve data from.

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What does * do in query?

Count. You may see both count(1) and count(*) in queries. They are interchangeable and both count the number of rows being selected.

Is Select * faster than select column?

SELECT by Column names is faster because you are only pulling in the columns needed rather than every column. This also depends quite a bit if your tables have primary keys and proper indexing. Selecting distinct and less than all columns will always be faster than selecting *.

Which is faster select or select column?

7 Answers. SELECT field is faster than select *. Because if you have more than 1 field/column in your table then select * will return all of those, and that requires network bandwidth and more work for the database to fetch all the other fields.

Is SQL case sensitive?

SQL Server is, by default case insensitive; however, it is possible to create a case sensitive SQL Server database and even to make specific table columns case sensitive. The way to determine a database or database object is by checking its “COLLATION” property and look for “CI” or “CS” in the result.

Why is using SELECT * Bad?

When you SELECT *, you’re often retrieving more columns from the database than your application really needs to function. This causes more data to move from the database server to the client, slowing access and increasing load on your machines, as well as taking more time to travel across the network.

Why should we not use * in SQL?

select * is an anti-pattern. So selecting columns is not a premature optimization. A few things off the top of my head …. If you specify columns in a SQL statement, the SQL execution engine will error if that column is removed from the table and the query is executed.

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Can we use distinct * in SQL?

The SQL SELECT DISTINCT Statement

The SELECT DISTINCT statement is used to return only distinct (different) values. Inside a table, a column often contains many duplicate values; and sometimes you only want to list the different (distinct) values.

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