Question

I often user a separate query to count rows to set a total variable when querying a table for paginated results.

Returns total users in table

SELECT Count(*) FROM users WHERE organizationId = :organizationId

Returns paginated results

SELECT * FROM users WHERE organizationId = :organizationId LIMIT :start, :end

public SearchResults findAll(User user, Paginator paginator) {
        HashMap<String, Object> namedParameters = new HashMap<String, Object>();
        namedParameters.put("organizationId", user.getOrganizationId());
        namedParameters.put("userId", user.getId());
        NamedParameterJdbcTemplate namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(dataSource);

        //Get count
        int total = namedParameterJdbcTemplate.queryForInt(SQL_FIND_ALL_COUNT, namedParameters);
        int start = 0;
        int end = total;

        if(paginator != null) {         
            start = paginator.getFirst();
            end = paginator.getCount();
        }

        namedParameters.put("start", start);
        namedParameters.put("end", end);
        SqlRowSet results = namedParameterJdbcTemplate.queryForRowSet(SQL_FIND_ALL, namedParameters);
        return new SearchResults(mapUser(results), total);
    }

The only reason for collecting the total is so I can return that as part of the search results, because its necessary for pagination so I know how many pages of results to display to the user without actually having to pass the results and find every record in the database.

Is there a way to do this in one query? So in other words, get the total count, while still using the LIMIT condition to only query for a specific amount (say 10 records at a time). If so, from a performance standpoint, does it make more sense to just keep these in separate queries?

Something like this?

SELECT *, (SELECT Count(*) FROM users WHERE organizationId = :organizationId) FROM users WHERE organizationId = :organizationId"

If the above query works, how do I actually get that subquery column, does it have a name I can reference?

results.getInt("count"); //?

Answer 1

Add an ALIAS after the subquery

SELECT  *, 
       (
        SELECT Count(*) 
        FROM users 
        WHERE organizationId = :organizationId
       ) `COUNT`
FROM users
WHERE organizationId = :organizationId

Alternative solution in your query is to use CROSS JOIN

SELECT  *, x.totalCount
FROM users, 
       (
        SELECT Count(*) totalCount
        FROM users 
        WHERE organizationId = :organizationId
       ) x
WHERE organizationId = :organizationId