forked from opengaussexamples/examples
22 lines
979 B
Plaintext
22 lines
979 B
Plaintext
SELECT DISTINCT? select_obj FROM select_tab where_clause? select_option? union_clause? ;
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select_obj = * | column* | function
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select_tab = table join_clause?
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select_option = GROUP BY | ORDER BY | HAVING
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function = COUNT() | SUM() | AVG() | MAX() | MIN()
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example:
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SELECT * FROM employees;
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SELECT employee_id, first_name, last_name FROM employees;
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SELECT * FROM employees WHERE department_id = 10;
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SELECT * FROM employees ORDER BY hire_date DESC;
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SELECT COUNT(*), AVG(salary) FROM employees;
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SELECT department_id, COUNT(*) FROM employees GROUP BY department_id;
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SELECT e.first_name, d.department_name FROM employees e JOIN departments d ON e.department_id = d.department_id;
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SELECT
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column1,
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CASE WHEN column2 > 0 THEN 'Positive' ELSE 'Non-positive' END as status,
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SUBSTR(column3, 1, 5) as substring_column3
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FROM table_name;
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SELECT column1, COUNT(column2) FROM table_name GROUP BY column1 HAVING COUNT(column2) > 10;
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