SQL? SELECT ? ??
SELECT ?? ?? ????? ????? ???? SQL ?? ? ?????. ??????? ?? ?? ??? ????? ???? ???? ? ?????. ??? ???? ???? ??? ?????.
SELECT ?? ??
SELECT column1, column2, ... FROM table_name WHERE condition ORDER BY column_name [ASC|DESC];
SELECT ?? ?? ??
- SELECT ?: ??? ?? ?????. ????? ?? ?? ????? *? ?????. ?:
SELECT first_name, last_name FROM employees;
- FROM ?: ???? ??? ???? ?????. ?:
SELECT * FROM orders;
- WHERE ?(?? ??): ??? ?? ?? ??????. ?:
SELECT * FROM customers WHERE city = 'New York';
- ORDER BY ??(?? ??): ?? ??? ?? ???? ?? ??? ????(ASC) ?? ????(DESC)?? ?????. ?:
SELECT * FROM products ORDER BY price DESC;
- GROUP BY ?(?? ??): ??? ??? ??? ?? ?? ?? ????? ?? ?? ??? ?????. ?:
SELECT department, COUNT(*) AS employee_count FROM employees GROUP BY department;
- HAVING ?(?? ??): ??? ?? GROUP BY? ??? ??? ??????. ?:
SELECT department, COUNT(*) AS employee_count FROM employees GROUP BY department HAVING COUNT(*) > 10;
SELECT? ???
1. ?? ? ??
SELECT * FROM employees;
- ?? ????? ?? ?? ?????.
2. ?? ? ??
SELECT first_name, last_name FROM employees;
- first_name ? last_name ?? ?????.
3. ?? ??
SELECT first_name AS "First Name", last_name AS "Last Name" FROM employees;
- ?? ??? ? ??? ????.
4. WHERE? ??? ???
SELECT * FROM orders WHERE order_date = '2024-01-01';
- 2024? 1? 1?? ??? ?? ??? ?????.
5. ??? ??
SELECT * FROM products ORDER BY price ASC;
- ?? ?????? ??? ??? ?????.
6. ???? ??
SELECT COUNT(*) AS total_employees FROM employees;
- ? ?? ?? ?????.
7. ??? ???
SELECT department, AVG(salary) AS average_salary FROM employees GROUP BY department;
- ??? ???? ????? ?? ??? ?????.
8. ????
SELECT * FROM customers WHERE city = 'London' AND age > 30;
- 30? ??? ?? ??? ?????.
9. ?? ?? ??
SELECT * FROM products LIMIT 5;
- ?? ????? ?? 5? ?? ?????.
SELECT ?? ???? ?? ??
??? ??:
????? ?? ?? ?? ?????.??? ??:
SUM(), COUNT(), AVG()? ?? ??? ???? ?? ? ??? ?????.??? ??:
???? ??? ?? ??? ??? ???? ????? ?????.??? ??:
?? ???? ???? ???? ???? ?? ??? ?????.
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SELECT column1, column2, ... FROM table_name WHERE condition ORDER BY column_name [ASC|DESC];
SELECT ?? ?
????? ??:
? ?? ??? ?? *? ???? ?? ??? ?? ?????.?? ??:
??? ???? ? ??? ? ?? ?? ? ????.?? ???:
???? ???? ?? ???? WHERE? ?????.?? ???:
?? ??? ????? ??? ??? ? ??? ???? ?????.
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SELECT ?? SQL?? ???? ???? ???? ? ???? ? ? ?????. ??? ??? ??? ??? ???? ??????? ????? ?? ????, ?? ?? ???? ????, ?????? ?? ??? ????? ??? ? ????.
?????. ?? Abhay Singh Kathayat???!
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? ???? ???(kaashshorts28@gmail.com)? ???? ?????.
? ??? SQL SELECT ? ???: ?? ???? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!
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MySQL ? ? ???? NULL ?? ?????
Jul 05, 2025 am 02:46 AM
MySQL?? NULL ?? ?? ? ? 1. ???? ?? ? ? ? ??? NotNull? ???? ?? ??? NULL? ?????. 2. iSnull ?? ISNOTNULL = ??! =; 3. Ifnull ?? Coalesce ??? ????? ???? ???? ? ??? ? ????. 4. ?? ?? ????? NULL ?? ?? ??? ?? ???? ??? ?? ? ORM ??? ?? ?? ?????? ??????. NULL? ???? ?? ?? ???? ??? ???? ?? ?? ?? ????. ??? ???? ??, ?? ? ???? ?? ? ??? ?? ??? ??? ?? ???????. ??? ??? ???? ??? ?? ?? ??? ????? ?? ? ????.
MySQL?? mysqldump? ???? ?? ??? ?????
Jul 06, 2025 am 02:55 AM
MySQLDump? MySQL ??????? ??? ??? ???? ???? ?????. ??????? ???? ?? ?? ? ?? ?? ???? SQL ??? ?????. 1. ?? ??? ????? ??? ?????? ??? ???? ??? SQL ???? ?????. 2. ??? ?????? ?? ??? ??? ???? TB ?? ???? ?? ???? ???? ????. 3. ???? ???-single transaction,-databases,-all-databases,-routines ?; 4. MySQL ??? ???? ?? ?? ?? ?? ?? ? ??? ?? ??? ???? ? ????. 5. ??? ????? ????? ?? ? ?? ??? ???? ?? ????.
MySQL?? ?????? ? ??? ?? ??
Jul 06, 2025 am 02:41 AM
MySQL ?????? ? ???? ??? ??? information_schema? ?? ????? ?? ? ??? ??? ? ????. 1. ?? ?????? ?? ?? : SQL ?? ???? selecttable_schemaas'database ', sum (data_length index_length)/1024/1024as'size (mb) 'frominformation_schema.tablessgroupbytable_schema; ?? ??????? ? ??? ??? ?? ??????? ???? ??? ?? ? ? ????. 2. ?? ??? ??? ?????? : selectta? ??????
MySQL?? ??? ?? ? ???? ??? ?????
Jul 08, 2025 am 02:51 AM
?? ?? ? ?? ?? ??? ??? ??? ?????? ?? ??? ??? ?????? ??? ?????? ?????? ??? ?????. ? ?? ?? ???? ????. ??, ??????, ??? ? ??? ?? ??? UTF8MB4? ???? ???? ShowCreatedAtabase/Table? ???? ? Alter ??? ??????. ??, ?????? ??? ? UTF8MB4 ?? ??? ???? ?? ?? ??? ????? SetNames? ??????. ??, ?? ??? ????? ???? UTF8MB4_UNICODE_CI? ???? ?? ? ????? ???? ???? ?????? ???? ?? ? ? ?? ?? ??? ????? ??????.
MySQL?? ??? ?? ???? ???? ??? ????.
Jul 05, 2025 am 02:42 AM
GroupBy? ???? ???? ????? ?? ??? ???? ? ???? ??? ? ??? ????? ? ?????. ?? ??, GroupByCustomer_ID? ???? ? ??? ? ???? ??? ? ????. ???? ? 1,000 ? ??? ? ??? ??? ?? ? ? ????. ?? ? ? ?? ??? GroupBy? ??????, ?? ?? ?? ???? ???? ??? ??? ? ? ????. ???? ???? ? ??? ? ??, ?? ?? ??? ? ?? ???? ???? ?????.
MySQL?? ???? ?? ? ?? ?? ??
Jul 08, 2025 am 02:50 AM
MySQL? ???? ??? ???? InnoDB ?? ??? ???? ??? ???? ???? ?????. 1. ????? ??? SQL ?? ????, ?? ?? ?? ?? ??? ?????. 2. ? ???? ???, ???, ?? ? ???? ?????. 3. ????? ???? ????? ??? STARTTRANSACTION, CONMING ? ROLLBACK???. 4. 4 ?? ?? ???? ?? ??, ?? ? ??, ?? ??? ?? ? ???? ?????. 5. ????? ???? ???? ?? ??? ??? ?? ??? ?? ?? ? ??? ????? ??????. ??? ????? ?? MySQL? ?? ???? ?? ??? ?? ? ? ????.
?? ? ?????? ???? MySQL ??????? ?????
Jul 07, 2025 am 01:50 AM
MySQL ??????? ???? ?? ???? ??? ?? ? ?????? ???? ????. ?? MySQL -U ??? ?? -P? ???? ????? ???? ???? ??? ?????? ??????. ?? ??????? ???? ?? ??? ??? ????? -h ?? ??? ???????. ??, mysql-u username-p database name ?? mysql-u username-p database name? ?? ??? ? ? ?? ??????? ?? ????? ??? ? ? SQL ??? ??? ? ????.
MySQL?? ??? ?? ? ???? ??
Jul 07, 2025 am 01:41 AM
MySQL? ?? ?? ? ???? ?? ??? ??? ??, ?? ?? ? ???? ??? ??? ? ?????. ??, ??? ??? UTF8MB4? ?? ?? ??? ?? ??? ?????. ?? ??? UTF8MB4_UNICODE_CI? ?? ?? ?? ??? ???? UTF8MB4_BIN? ?? ?????. ??, ?? ??? ?? ??? ??, ??????, ??? ? ??? ??? ? ????. ??? ??? ?? UTF8MB4 ? UTF8MB4_UNICODE_CI? ?? ? ???? ???? ?? ????. ??, ?? ??? ?? ??? ?? ???? ?? ??, ?? ?? ???? ??? ??? ?? ???? ???? ??? ???? ???? ???????. ?? ?? ??? ???? ?? ???? ? ??? ? ?? ??? ???????.
