Community
Learn
Tools Library
AI Tools
Leisure
search
English
Article Tags
Home Technical Articles Database SQL
How to view the current date in SQL

How to view the current date in SQL

Methods to view the current date in SQL: Use the CURRENT_DATE function: Return the current system date. Use the GETDATE() function (Microsoft SQL Server only): Returns the current system date. Use NOW() function (MySQL and MariaDB only): Returns the current system date.

Apr 10, 2025 am 11:06 AM
mysql
How to run SQL stored procedures

How to run SQL stored procedures

SQL stored procedures are precompiled collections of SQL statements used to perform complex operations and improve performance. The steps to run a stored procedure include: 1) creating a stored procedure (using CREATE PROCEDURE); 2) calling a stored procedure (using EXEC syntax, specifying schema, name, and parameters).

Apr 10, 2025 am 11:03 AM
How to optimize sql query slow

How to optimize sql query slow

Slowly running SQL query optimization strategy: Determine query bottlenecks: Use the EXPLAIN or EXPLAIN ANALYZE statement. Create an appropriate index: Create an index for frequently used columns. Optimize table joins: Use HASH or MERGE JOIN to explicitly specify the connection conditions. Rewrite subquery: Use the connection or EXISTS/NOT EXISTS condition. Optimized sorting and grouping: Use column sorting or grouping of indexes. Utilize query cache: Stores executed query plans. Adjust database configuration: optimize parameters such as memory allocation. Hardware upgrade: Consider adding memory or replacing CPU.

Apr 10, 2025 am 11:00 AM
How to delete duplicate data in sql

How to delete duplicate data in sql

Delete duplicate data in SQL by using the DISTINCT keyword to remove duplicate values ​​from the query results. Use the DISTINCT keyword to delete duplicate rows from the table together with the DELETE statement.

Apr 10, 2025 am 10:57 AM
How to query all tables in the database in SQL

How to query all tables in the database in SQL

The commands for querying all tables in the database vary by DBMS. The following are three common DBMS commands: MySQL: SHOW TABLES;PostgreSQL: SELECT * FROM pg_catalog.pg_tables;SQLite: SELECT name FROM sqlite_master WHERE type = 'table';

Apr 10, 2025 am 10:54 AM
mysql
How to fix corruption of sql database

How to fix corruption of sql database

SQL database corruption can be repaired by the following steps: 1. Determine the corruption type (page corruption, index corruption, file corruption); 2. Back up the database; 3. Run the DBCC CHECKDB command to check for corruption; 4. Use the DBCC REPAIR_ALLOW_DATA_LOSS, DBCC REPAIR_FAST, or DBCC REPAIR_REBUILD commands to repair the corruption according to the corruption type; 5. If the corruption is serious, rebuild the database; 6. Run the DBCC CHECKDB command to verify the repair.

Apr 10, 2025 am 10:51 AM
数据丢失
How to display multiple lines as one line in SQL

How to display multiple lines as one line in SQL

Tips for combining multiple rows of data into one row in SQL include: using the CONCAT function to connect strings, such as dividing names into full names. Use the GROUP_CONCAT function to connect the values ​​of all rows in the group, such as grouping the product list. Use the STRING_AGG function to connect strings and specify delimiters, such as grouping skill lists and adding delimiters. Use the FOR XML PATH('') clause to convert the query results to an XML string. Use the STUFF function to insert substrings, such as converting the customer name to a line with an XML tag.

Apr 10, 2025 am 10:48 AM
How to solve SQL injection

How to solve SQL injection

Solutions for SQL injection include: Escape special characters with parameterized queries Use SQL injection filters Use whitelist validation to enhance input validation Use WAF (Web Application Firewall) to maintain software updates Provide education and training

Apr 10, 2025 am 10:45 AM
sql语句
How to reload SQL

How to reload SQL

There are four ways to deduplicate in SQL: 1. DISTINCT keyword: eliminates duplicate values ​​in a single column. 2. GROUP BY clause: Group by column and return unique rows. 3. Subquery: Select a unique value from the main query. 4. Collection operator: merge result sets and eliminate duplicate values.

Apr 10, 2025 am 10:42 AM
How to call stored procedures in SQL

How to call stored procedures in SQL

Syntax for calling stored procedures in SQL: CALL procedure_name(parameter1, parameter2, ...). The parameter type of stored procedures can be input, output, or input/output type, and the syntax is: CALL procedure_name(IN | OUT | INOUT parameter_name datatype). To get the value of the output parameter, use the @ symbol followed by the parameter name: SELECT @output_parameter_name;.

Apr 10, 2025 am 10:39 AM
How to delete a row of data in a table in SQL

How to delete a row of data in a table in SQL

The DELETE statement is used to delete a row of data from a table. The syntax is: DELETE FROM table_name WHERE condition; the steps include: establishing a connection, writing a statement, executing a statement, confirming changes; Notes: permanently deleting data, restriction conditions, and only applicable to tables.

Apr 10, 2025 am 10:36 AM
How to write a SQL delete statement

How to write a SQL delete statement

The SQL delete statement is DELETE FROM, which is used to delete rows from the specified table. The syntax is: DELETE FROM table_name WHERE condition. condition is an optional condition that specifies the row to be deleted. If no conditions are specified, all rows are deleted. Example: DELETE FROM customers WHERE customer_id = 2; Delete line with customer_id of 2.

Apr 10, 2025 am 10:33 AM
How to write sql contains statements

How to write sql contains statements

SQL contains statements allow the inclusion of external SQL statements or tables in the current statement, which are used to reuse code and enhance modularity. Syntax: 1. Include file: INCLUDE 'file_path'; 2. Include table: INCLUDE 'table_name'; This statement can be used to add content from external files or tables to the current query, enhancing the reusability and modularity of SQL statements.

Apr 10, 2025 am 10:30 AM
How to write sql statements does not mean

How to write sql statements does not mean

In SQL, two operators can be used for the non-equal sign: != and <>. != is the most common form, indicating that the two values ​​are not the same. The <> operator functions the same, but it is recommended to use != because it is more commonly used and easy to understand.

Apr 10, 2025 am 10:27 AM
sql语句

Hot tools Tags

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Assassin's Creed Shadows: Seashell Riddle Solution
1 months ago By DDD
What's New in Windows 11 KB5054979 & How to Fix Update Issues
3 weeks ago By DDD
Where to find the Crane Control Keycard in Atomfall
1 months ago By DDD
How to fix KB5055523 fails to install in Windows 11?
2 weeks ago By DDD
InZoi: How To Apply To School And University
3 weeks ago By DDD
Show More

Hot Tools

vc9-vc14 (32+64 bit) runtime library collection (link below)

vc9-vc14 (32+64 bit) runtime library collection (link below)

Download the collection of runtime libraries required for phpStudy installation

VC9 32-bit

VC9 32-bit

VC9 32-bit phpstudy integrated installation environment runtime library

PHP programmer toolbox full version

PHP programmer toolbox full version

Programmer Toolbox v1.0 PHP Integrated Environment

VC11 32-bit

VC11 32-bit

VC11 32-bit phpstudy integrated installation environment runtime library

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Show More

Hot Topics

Where is the login entrance for gmail email?
7750
15
Java Tutorial
1643
14
CakePHP Tutorial
1397
52
Laravel Tutorial
1293
25
PHP Tutorial
1234
29
Show More