What is the usage of mysql or

mysql or syntax is generally used for queries with multiple conditions. Its usage syntax is such as "SELECT * FROM WHERE p.`act_type` = 4 or p.`act_type` =...".

#The operating environment of this article: Windows7 system, mysql8, Dell G3.

What is the usage of or in mysql?

Examples of usage of or statement in MySQL

1.Usage of or syntax in mysql , points to note when using or in mysql syntax. The project encountered a pitfall, and there was an error in querying the reward data while traversing it! ! !

$sql = 'SELECT 
        * 
      FROM 
        `vvt_spread_doubleegg_exchange_award` AS p
      WHERE
        p.`act_type` = 4 or p.`act_type` = 5
      AND
        p.`user_id` = ' .$user_id
      ;

The or syntax in sql is generally used for queries with multiple conditions. The above syntax query is equivalent to: two data sets queried by sql.

$sql = 'SELECT * FROM `vvt_spread_doubleegg_exchange_award` AS p WHERE p.`act_type` = 4;
$sql = 'SELECT * FROM `vvt_spread_doubleegg_exchange_award` AS p WHERE p.`act_type` = 5 AND p.`user_id` = ' .$user_id;

2. If you want to query the data set of act_type = 4 and user_id = 11123 or equal to p.`act_type` = 5 and user_id = 11123, you must add () to the conditions on both sides.

$sql = 'SELECT 
        * 
      FROM 
        `vvt_spread_doubleegg_exchange_award` AS p
      WHERE
        （p.`act_type` = 4 or p.`act_type` = 5）
      AND
        p.`user_id` = ' .$user_id
      ;

Recommended learning: "mysql video tutorial"

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