A must-have method for querying data - setFetchMode () in php

PDOStatement::fetch()

PDOStatement::fetch    ([ int $fetch_style   [, int $cursor_orientation = PDO::FETCH_ORI_NEXT   [, int $cursor_offset = 0  ]]] ) : mixed

$fetch_styleThis value must be one of the PDO::FETCH_* series of constants:

• PDO::FETCH_ASSOC: Returns an array whose index is the result set column name

• PDO::FETCH_BOTH (default): Returns an array whose index is the result set column name and the column number starting with 0 Array

• ## PDO::FETCH_BOUND: Returns TRUE and assigns the column value in the result set to the PHP variable bound by the PDOStatement::bindColumn() method.

• PDO::FETCH_CLASS: Returns a new instance of the request class, mapping the column names in the result set to the corresponding attribute names in the class. If fetch_style contains PDO::FETCH_CLASSTYPE (for example: PDO::FETCH_CLASS | PDO::FETCH_CLASSTYPE), the class name is determined by the value of the first column.

• PDO::FETCH_INTO: Update an existing instance of the requested class, mapping the columns in the result set to the named attributes in the class

• PDO::FETCH_LAZY: Use PDO::FETCH_BOTH and PDO::FETCH_OBJ in combination to create an object variable name for access

• PDO::FETCH_NUM: Returns an index starting with 0 Array of result set column numbers

• PDO::FETCH_OBJ: Returns an anonymous object whose attribute name corresponds to the result set column name

When using the fetch() method by default, we will get double data in the database:

But in the database, there is really only a simple piece of data:

If you only want to get a simple index as the result set column name, you only need to set it simply:

$statement->setFetchMode(PDO::FETCH_ASSOC);

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