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8 months ago

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Select count(*) from multiple tables

QuestionHow can I select count(*) from two different tables (call them tab1 and tab2) having as result:Count_1 Count_2 123 456I've tried this:select count(*) Count_1 from schema.tab1 union all select count(*) Count_2 from schema.tab2But all I have is:Count_1 123 456Answer1SELECT ( SELECT COUNT(*) FROM tab1 ) AS count1, ( SELECT COUNT(*) FROM tab2 ) AS count2 FROM dualCommentswhy do you need dual? what does that mean?It's a f ...

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8 months ago

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COUNT(*) from multiple tables in MySQL

QuestionHow do I go about selecting COUNT(*)s from multiple tables in MySQL?Such as:SELECT COUNT(*) AS table1Count FROM table1 WHERE someCondition JOIN?? SELECT COUNT(*) AS table2Count FROM table2 WHERE someCondition CROSS JOIN? subqueries? SELECT COUNT(*) AS table3Count FROM table3 WHERE someConditionEdit:The goal is to return this:+-------------+-------------+-------------+ | table1Count | table2Count | table3Count | +-------------+-------------+-------------+ | 14 | 27 | 0 ...

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8 months ago

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ORDER BY with Multiple Counts and SUM()

I am struggling to get the syntax correct below. I've tried various unions and joins without success.I need to SUM the 3 totals as 'totcount'. The data table is very large and was hoping to find a better way to obtain totcount than a 4th subquery. SELECT location.*,data.status, (SELECT COUNT(data.id) FROM data WHERE data.locid=location.locid AND data.status='NEW') AS newcount, (SELECT COUNT(data.id) FROM data WHERE data.locid=location.locid AND data.status='IN-PRO ...

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8 months ago

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Obtain the sum of count of multiple schema and tables in one query in mysql

QuestionThe query belows return 4 rows and it's good. But i need also to sum the results of all the counts in the same query. How to achieve it? I've tried different things but i get sintax errors.SELECT COUNT(*) FROM `schema1`.`table` WHERE STATE = 17 AND LEVEL = 1 UNION ALL SELECT COUNT(*) FROM `schema2`.`table` WHERE STATE = 17 AND LEVEL = 1 UNION ALL SELECT COUNT(*) FROM `schema3`.`table` WHERE STATE = 17 AND LEVEL = 1 UNION ALL SELECT COUNT(*) FROM `schema4`.`table` WHERE STATE = 17 AND LEV ...

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8 months ago

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Count multiple tables as one count

QuestionI have seen how to do multiple counts for different tables, but never how to combine them all into one. I have a MySQL DB where I am running the following query:SELECT characters.name, COUNT(*) AS wiki_unlocks FROM wiki_items INNER JOIN characters ON characters.character_id=wiki_items.character_id GROUP BY wiki_items.character_id ORDER BY wiki_unlocks DESC LIMIT 10;This is giving me the following which is great:name wiki_unlocks player1 2 player2 ...

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8 months ago

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What is a Database Schema?

In database terms, a  (pronounced “skee-muh” or “skee-mah”) is the organisation and structure of a database. Both schemas and schemata can be used as plural forms.A schema contains schema objects, which could be tables, columns, data types, views, stored procedures, relationships, primary keys, foreign keys, etc.A database schema can be represented in a visual diagram, which shows the database objects and their relationship with each other.A basic schema diagram representing a small three-t ...

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