PHP MySQL检查一个表是否有主键

Question

我会查询我的MySQL服务器来检查一个表是否有主键？喜欢的东西：

 

if(mysql_send("SELECT TABLE table HAS PRIMARY KEY") == TRUE) { 
    // do stuff here 
} 
 

Answer 1

SHOW INDEXES FROM TABLE WHERE Key_name = 'PRIMARY' 

Answer 2

SELECT EXISTS(
    SELECT 1 
    FROM information_schema.columns 
    WHERE table_schema = 'db' 
    and table_name='table name' 
    and column_key = 'PRI' 
) As HasPrimaryKey