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How to do UNION query with PHP CodeIgniter framework's active record query format?
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The UNION should run in parallel, at least since SQL Server 2005. It doesn't make a difference if the tables are located on different drives or the same drive. In the modern world, disk can be virtual, or have multiple read heads. The distinction between one drive and more than one drive is less and less relevant.
To combine result set of two or more queries using the UNION operator, these are the basic rules that you must follow: First, the number and the orders of columns that appear in all SELECT statements must be the same. Second, the data types of columns must be the same or compatible.
Here is the query to count on the union query. mysql> select count(*) as UnionCount from -> ( -> select distinct UserId from union_Table1 -> union -> select distinct UserId from union_Table2 -> )tbl1; The following is the output displaying the count.
CodeIgniter's ActiveRecord doesn't support UNION, so you would just write your query and use the ActiveRecord's query method.
$this->db->query('SELECT column_name(s) FROM table_name1 UNION SELECT column_name(s) FROM table_name2'); If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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