Advertisement

Tag: left-join

Select query to show missing values per day as 0

I have one table with product id’s and another with daily data for these products. When there is no data I want to return 0 instead of no value at all. I tried using a left join but this doesn’t give the resultset I want since the table I can join on has product id’s only, not per day. I

How to count missing rows in left table after right join?

There are two tables: Table education_data (list of countries with values by year per measured indicator). create table education_data (country_id int, indicator_id int, year date, value float ); …

Postgres LEFT JOIN not returning nulls?

Not sure why this is happening, but I have this query: And the item table has 100 elements. I’m looking for the resulting rows to be grouped by user_id and have each array be 100 items long. That is, if the value is not present in the vote table, to just instead sub in a 0 in its place. Unfortunately

Try to define a left join only with where condition

I try to find a particular SQL statement to replace an old SQL query. To summarize, I try to make a left join only with where conditions. Here is my test environment: I fill the tables with some data: The usual way for a left join is this: This query returns 1266 rows. But in the old application, which I

Select unmatched records from two tables with a filter on second table

I have 2 mysql tables a and b. I need to show all records in a that are not in b using a common column ‘ID’. Normally this is pretty straight forward but my problem here is this: I need to put a where clause on table b because I’m not interested in all unmatched records just the ones that

Left Join return not all row

I have two tables: baseresulttables and historyviewdemands. I want to get the first n entries from baseresulttables, and if there are values for them in historyviewdemands. But the query works like an inner join. What am I doing wrong? baseresulttables historyviewdemands Query: reuslt Answer Using LIMIT without ORDER BY is fairly meaningless, because you aren’t telling MySQL which order to