tagged [join]
Count with IF condition in MySQL query
Count with IF condition in MySQL query I have two tables, one is for news and the other one is for comments and I want to get the count of the comments whose status has been set as approved. ``` SELEC...
- Modified
- 31 Mar at 12:43
How to join multiple collections with $lookup in mongodb
How to join multiple collections with $lookup in mongodb I want to join more than two collections in MongoDB using the aggregate `$lookup`. Is it possible to join? Give me some examples. Here I have t...
- Modified
- 21 Feb at 20:53
Can we use join for two different database tables?
Can we use join for two different database tables? Can we use the join operation for two tables from different databases? If yes, how do I do it? Both databases are on the same server and DBMS is the ...
How to return rows from left table not found in right table?
How to return rows from left table not found in right table? I have two tables with similar column names and I need to return records from the left table which are not found in the right table? I have...
- Modified
- 18 Jan at 17:49
Include with FromSqlRaw and stored procedure in EF Core 3.1
Include with FromSqlRaw and stored procedure in EF Core 3.1 So here's the deal - I am currently using EF Core 3.1 and let's say I have an entity: When I access the `DbSet Entities` normal way, I inclu...
- Modified
- 17 Dec at 20:18
CROSS JOIN vs INNER JOIN in SQL
CROSS JOIN vs INNER JOIN in SQL What is the difference between `CROSS JOIN` and `INNER JOIN`? ``` SELECT Movies.CustomerID, Movies.Movie, Customers.Age,
- Modified
- 12 Dec at 08:55
LEFT JOIN only first row
LEFT JOIN only first row I read many threads about getting only the first row of a left join, but, for some reason, this does not work for me. Here is my structure (simplified of course) ``` rel_id | ...
- Modified
- 17 Jul at 14:50
Removing extra commas from string after using String.Join to convert array to string (C#)
Removing extra commas from string after using String.Join to convert array to string (C#) I'm converting an array into a string using `String.Join`. A small issue I have is that, in the array some ind...
MySQL INNER JOIN select only one row from second table
MySQL INNER JOIN select only one row from second table I have a `users` table and a `payments` table, for each user, those of which have payments, may have multiple associated payments in the `payment...
- Modified
- 27 Feb at 14:49
SQL JOIN and different types of JOINs
SQL JOIN and different types of JOINs What is a SQL `JOIN` and what are different types?
Does "where" position in LINQ query matter when joining in-memory?
Does "where" position in LINQ query matter when joining in-memory? Say we are executing a LINQ query that joins two in-memory lists (so no DbSets or SQL-query generation involved) and this query also ...
- Modified
- 18 Dec at 12:8
Update statement with inner join on Oracle
Update statement with inner join on Oracle I have a query which works fine in MySQL, but when I run it on Oracle I get the following error: > SQL Error: ORA-00933: SQL command not properly ended 0093...
- Modified
- 20 Nov at 09:39
Join vs. sub-query
Join vs. sub-query I am an old-school MySQL user and have always preferred `JOIN` over sub-query. But nowadays everyone uses sub-query, and I hate it; I don't know why. I lack the theoretical knowled...
pandas three-way joining multiple dataframes on columns
pandas three-way joining multiple dataframes on columns I have 3 CSV files. Each has the first column as the (string) names of people, while all the other columns in each dataframe are attributes of t...
How to join on multiple columns in Pyspark?
How to join on multiple columns in Pyspark? I am using Spark 1.3 and would like to join on multiple columns using python interface (SparkSQL) The following works: I first register them as temp tables....
- Modified
- 5 Jul at 08:24
Difference between natural join and inner join
Difference between natural join and inner join What is the difference between a natural join and an inner join?
- Modified
- 1 Jul at 19:2
1052: Column 'id' in field list is ambiguous
1052: Column 'id' in field list is ambiguous I have 2 tables. `tbl_names` and `tbl_section` which has both the `id` field in them. How do I go about selecting the `id` field, because I always get this...
- Modified
- 15 Jun at 20:22
Combine two pandas Data Frames (join on a common column)
Combine two pandas Data Frames (join on a common column) I have 2 dataframes: restaurant_ids_dataframe ``` Data columns (total 13 columns): business_id 4503 non-null values categories 4503 non-nu...
Join between tables in two different databases?
Join between tables in two different databases? In MySQL, I have two different databases -- let's call them and . Is it possible to perform a join between a table that is in database , to a table that...
How to concatenate two collections by index in LINQ
How to concatenate two collections by index in LINQ What could be a LINQ equivalent to the following code? ``` string[] values = { "1", "hello", "true" }; Type[] types = { typeof(int), typeof(string)...
- Modified
- 24 Jan at 10:27
SQL Server: Multiple table joins with a WHERE clause
SQL Server: Multiple table joins with a WHERE clause I'm using SQL Server and I'm having a difficult time trying to get the results from a `SELECT` query that I want. I've tried joining in different o...
- Modified
- 5 Nov at 22:9
Explicit vs implicit SQL joins
Explicit vs implicit SQL joins Is there any efficiency difference in an explicit vs implicit inner join? For example: vs.
query specified join fetching, but the owner of the fetched association was not present in the select list
query specified join fetching, but the owner of the fetched association was not present in the select list I'm selecting two id columns but get error specified: ``` org.hibernate.QueryException: **que...
What is the syntax for an inner join in LINQ to SQL?
What is the syntax for an inner join in LINQ to SQL? I'm writing a LINQ to SQL statement, and I'm after the standard syntax for a normal inner join with an `ON` clause in C#. How do you represent the ...
- Modified
- 21 Aug at 10:31