Question

I have created a the following strings:

set l_project_name = concat("UPPER(a.project_name) like UPPER ('%",projectName,"%')");
set l_project_type = concat(" OR UPPER(a.project_type) like UPPER('%",projectType,"%')");
set l_project_description = concat(" OR UPPER(a.project_description) like UPPER('%",projectDescription,"%')");

set l_full_search_clause = concat(l_project_name ,l_project_type, l_project_description); 

The result of the string: l_full_search_clause is :
UPPER(a.project_name) like UPPER(‘%order%’)

I have a select clause that i need to use this string that i have created that contains this where clause. So, i have the following :
select * from projects
where l_full_search_clause

But, of course, MYSQL reads l_full_search_clause as is and not as a variable. How can i tell MYSQL that the condition is a variable string ?

This sql is in a MYSQL stored procedure .. so its just plain sql .. I am calling this stored procedure from C#, MVC3

Answer 1

Try this:

SET @query = "SELECT * FROM projects WHERE ";

SET @l_project_name = CONCAT("a.project_name LIKE '%", projectName, "%'");
SET @l_project_type = CONCAT(" OR a.project_type LIKE '%", projectType, "%'");
SET @l_project_description = CONCAT(" OR a.project_description LIKE '%", projectDescription, "%'");

SET @l_full_search_clause = CONCAT(@l_project_name, @l_project_type, @l_project_description); 

SET @query = CONCAT(@query, @l_full_search_clause);

PREPARE stmt FROM @query;
EXECUTE stmt;

I believe you have to use the @var syntax for variables. Also, to execute a query which is stored in a string, you have to use PREPARE and EXECUTE.

And you don’t have to use UPPER on strings. By default, MySQL compares strings case-insensitively. You can ensure that by looking at collation type for you fields. ci_ ones stand for “case insensitive”.