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Tag: join

I wonder using INNER JOIN and equality operator is faster or using IN when I try to filter data from a table by another table’s column

While I’m trying to get all accounts, which received message from foo@gmail.com. I want to know about the performance of two following query. or Thanks! Answer Always use the first query in such situations. Don’t use DISTINCT inside an IN clause subquery, though. Don’t try to tell the DBMS how to perform the IN. (Well, a good DBMS should simply

SQL Select from multiple tables and count third

I want to count number of rows in table that is referenced by two fields of other tables. I’ve the following structure Result that I want to achieve The statement that I’ve tried, but getting error at right join What I’m missing? Answer You are quite close. Main problems with your query: you are mixing implicit and explicit joins: just

SQL Join on table with revision dates

I am about to begin working on a solution for my company in SQL that requires me to link product category mappings based on a SKU number. The problem is that the category mappings can change, and they will have a date associated with the change. For example: Product 1 is currently mapped to category A. User realizes it was

Bigquery Full Join ON multiple conditions

I want to perform a Full Outer join on two tables with multiple conditions to result all the matching records along with unmatched records from both tables. Tbl1 is a bigger table with 21 M records and Tbl2 has 5k rows, like the example query below. But the outer join cannot be performed with OR conditions because of the error

MySQL – Joins and Subqueries [closed]

Closed. This question needs debugging details. It is not currently accepting answers. Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question. Closed 2 years ago. Improve this question I’m looking a question that asks ‘List for each year the name of

Conditionally joining from multiple tables

Does SQL allow some form of conditional “table choosing” within the Join statement? ie. selecting a different table to join based on a predefined variable/condition. The error I get when attempting this method is ORA-00905: missing keyword. Answer No. Neither SQL nor Oracle allow this, unless you use dynamic SQL. Assuming the tables have the same columns, you could write

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