Join two tables with comma separated values
SELECT a.nid, GROUP_CONCAT(b.name ORDER BY b.id) DepartmentName FROM Notes a INNER JOIN Positions b ON FIND_IN_SET(b.id, a.forDepts) > 0 GROUP BY a.nid SQLFiddle Demo
left-join
Delete from one table with join
I am not sure about your requirement. What I understood from your question is you want to delete all the emails of jobs which are closed. try this one; DELETE e FROM emailNotification e LEFT JOIN jobs j ON j.jobId = e.jobId WHERE j.active = 1 AND CURDATE() < j.closeDate
Entity Framework include with left join is this possible?
Yes, it is possible. Firstly, .Include does a LEFT OUTER JOIN, using the navigational property you pass through. This is how you would explicitly do a LEFT JOIN between Student and StudentDescription: var query = from s in ctx.Students from sd in s.StudentDescriptions.DefaultIfEmpty() select new { StudentName = s.Name, StudentDescription = sd.Description }; As you … Read more
Select first record in a One-to-Many relation using left join
After playing around a bit, this turns out to be trickier than I’d expected! Assuming that table_b has some single column that is unique (say, a single-field primary key), it looks like you can do this: SELECT table_a.code, table_a.emp_no, table_b.city, table_b.county FROM table_a LEFT JOIN table_b ON table_b.code = table_a.code AND table_b.field_that_is_unique = ( SELECT … Read more
Access 2007 – Left Join to a query returns #Error instead of Null
While the query should return Null based on the join type, as Allen Browne states in his article, Bug: Outer join expressions retrieved wrongly, “Instead, it behaves as if [the JET query optimizer] is evaluating the expression after it has returned the results from the lower-level query.” Consequently, you must select the calculated field using … Read more
Postgres LEFT JOIN with WHERE condition
left join two tables with a where condition It’s typically wrong to use a LEFT [OUTER] JOIN and then filter with a WHERE condition, thereby voiding the special feature of a LEFT JOIN to include all rows from the left table unconditionally. Detailed explanation: Explain JOIN vs. LEFT JOIN and WHERE condition performance suggestion in … Read more
SQL SELECT from multiple tables
SELECT p.pid, p.cid, p.pname, c1.name1, c2.name2 FROM product p LEFT JOIN customer1 c1 ON p.cid = c1.cid LEFT JOIN customer2 c2 ON p.cid = c2.cid
Explain JOIN vs. LEFT JOIN and WHERE condition performance suggestion in more detail
Effectively, WHERE conditions and JOIN conditions for [INNER] JOIN are 100 % equivalent in PostgreSQL. (It’s good practice to use explicit JOIN conditions to make queries easier to read and maintain, though). The same is not true for a LEFT JOIN combined with a WHERE condition on a table to the right of the join. … Read more
LEFT JOIN only first row
If you can assume that artist IDs increment over time, then the MIN(artist_id) will be the earliest. So try something like this (untested…) SELECT * FROM feeds f LEFT JOIN artists a ON a.artist_id = ( SELECT MIN(fa.artist_id) a_id FROM feeds_artists fa WHERE fa.feed_id = f.feed_id ) a
Difference in MySQL JOIN vs LEFT JOIN
I thought that by not specifying a type of join it was assumed to be a LEFT JOIN. Is this not the case? No, the default join is an INNER JOIN. Here is a visual explanation of SQL joins. Inner join Left join