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When making a MySQL query with no WHERE constraints, most people use WHERE 1 in the query. However, omitting WHERE 1 does not influence the query. Is there a difference between the two? Is one considered to be the best practice?
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In MySQL “Where 1=1” results in all the rows of a table as this statement is always true. An example to better unerstand this statement is given as follows − First, a table is created with the help of the create command.
If you have worked with SQL databases before, you might have come across the statement WHERE 1=1. It is a common statement that is used to return all the records from a given table. The statement where 1=1 in SQL means true. It is the same operation as running the select statement without the where clause.
The WHERE clause is used to filter records. It is used to extract only those records that fulfill a specified condition.
SQL Injection Based on 1=1 is Always True The original purpose of the code was to create an SQL statement to select a user, with a given user id.
I don't think it's a matter of best practice, but people sometimes use it to make building dynamic queries a bit easier.
string sql = "SELECT * FROM mytable WHERE 1 "; if ( somecondition ) { sql += "AND somefield = somevalue "; } if ( someothercondition ) { sql += "AND someotherfield = someothervalue "; } ... etc Without the WHERE 1 in there I would need to check in each if block whether I needed to put in a WHERE or an AND.
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It's not necessary. 99.9% of the time it just means the query was dynamically constructed and putting in WHERE 1 leads to simpler logic for dynamic conditional clauses, meaning you can just keep adding AND id = 3 to the end of the query and it won't break the syntax. If you don't have WHERE 1 you have to worry about whether or not there's a WHERE clause and whether to prepend your condition with AND or not.
So it's just laziness basically.
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