在sql中执行以下查询有什么问题

SELECT jobs.id,jobs.title, jobs.budget, jobs.views_count, jobs.is_active, count(job_applications.id) as count
    FROM jobs 
    LEFT JOIN job_applications ON job_applications.job_id = jobs.id WHERE jobs.user_id ='.$id.'' AND jobs.title=''.$title.' group by jobs.id

This query give error:

syntax error, unexpected '=', expecting ',' or ';'

The problem is with PHP, not with SQL.

You have messed up with single quotes.

Updated query:

$sql = "SELECT jobs.id,jobs.title, jobs.budget, jobs.views_count, jobs.is_active, count(job_applications.id) as count
        FROM jobs 
        LEFT JOIN job_applications ON job_applications.job_id = jobs.id WHERE jobs.user_id ='$id' AND jobs.title='$title' group by jobs.id";

try like this

$your_query = "SELECT jobs.id,jobs.title, jobs.budget, jobs.views_count, jobs.is_active, count(job_applications.id) as count FROM jobs 
    LEFT JOIN job_applications ON job_applications.job_id = jobs.id WHERE jobs.user_id =".$id." AND jobs.title='".$title."' group by jobs.id";

Watch your quotes. Here is your query fixed without double use of quotes:

$query = 'SELECT 
    jobs.id,
    jobs.title, 
    jobs.budget, 
    jobs.views_count, 
    jobs.is_active, 
    count(job_applications.id) as count
    FROM jobs 
LEFT JOIN job_applications ON job_applications.job_id = jobs.id 
WHERE 
    jobs.user_id ='.$id.' 
    AND jobs.title='.$title.' 
group by jobs.id';

If $title pertains to a string, use the following, as pointed out by @daiscog:

$query = 'SELECT 
    jobs.id,
    jobs.title, 
    jobs.budget, 
    jobs.views_count, 
    jobs.is_active, 
    count(job_applications.id) as count
    FROM jobs 
LEFT JOIN job_applications ON job_applications.job_id = jobs.id 
WHERE 
    jobs.user_id ='.$id.' 
    AND jobs.title=\''.$title.'\' 
group by jobs.id';

Change this

jobs.user_id ='.$id.'' AND jobs.title=''.$title.'

to

jobs.user_id ='.$id.' AND jobs.title='.$title.'