10 recommended articles about modifying statements

To modify records, you can use the UPDATE statement. The syntax format is as follows: UPDATE data table name Set column_name = new_value1, column_name2 = new_value2,...[where condition] Among them, the Set clause indicates the column to be modified. With their given values, the where clause is optional. If given it specifies which rows in the record should be updated. Otherwise, all rows in the record will be updated. For example, suppose there is a table called admin, and we want to change the password of Tom in the table from 111 to 222. The statement is as follows: UPDATE admin Set password = '222' where user = 'Tom'; Note: Be sure to ensure that when updating The correctness of the where clause. Once the where clause is wrong, all changed data will be destroyed. Delete records in the database. If some data have lost their meaning or are wrong, they need to be deleted. At this time, you can use the DELECT statement, which

1. MySQL modification and delete statement operations ( MYSQL statement operation tutorial 2)

## Introduction: Modify records To perform modification operations, you can use the UPDATE statement. The format of the syntax is as follows: UPDATE data table name set column_name = new_value1, column_name2 = new_value2,...[where condition] Among them, the set clause indicates the columns to be modified and their given values, and the where clause is optional. If given it specifies which rows in the record should be updated, otherwise, all rows in the record will be updated. For example, suppose there is a table called admin. We want to change the password of Tom in the table from 111 to 222. The statement is as follows:

2. php executes sql return value Related issues

Introduction: PHP executes sql return value problem PHP executes sql return value problem. When executing the query, the ID is returned successfully. The query statement is correct. For example, the ID of the query is not correct. It exists, but the query is empty. What does it return? What does the query error return? When the modification is executed, what is returned successfully? The modification statement is correct, but the modification is empty. What is returned? What will be returned if the error is modified? When the execution is increased, what is returned successfully, and what is returned when an error is added? Execute deletion, what is returned successfully, the deletion statement is correct, but the deletion is empty return

3. Web program implements simple version of PL/SQL and Excel table configuration backup SQL Statement

Introduction: In order to cope with the release, I am used to using Excel to record every database modification statement. But when releases are frequent, maintaining this document becomes very difficult. So I want to develop a set of

4. Oracle modify table structure statements

Introduction: 1. Modify the fields of the table: Modify The data type of a column (generally limited to the modification length, there are many restrictions when modifying to a different type): Syntax: ALTER TABLE table name MODIFY (

5. Mysql automatically submits the query with Impact of return

Introduction: The impact of Mysql automatic submission on queries. In database application programming, the automatic submission mode of the database is usually turned off in order to modify the execution efficiency of the statement. , and then commit the changes using transactions. Then the problem arises. The following is a simplified program, using the Mysql C API: MYSQL *conn=mysql_init(NULL); mysql_real_conn

6. Vertica modifies the length of fields with UNIQUE constraints

Introduction: table structure such as CREATE TABLE IF NOT EXISTS public.user (id PRIMARY KEY, name varchar (32) NOT NULL UNIQUE, ...); Modify the statement alter table public.user alter name set data type varchar(52); Due to the "UNIQUE" condition, if the statement is executed directly, the following error will be reported

7. This is for record keeping (3) Classification of Oracle SQL statements

Introduction: 1. Data manipulation Language DML (Data Manipulation Language): includes retrieval (query) and update (insert, modify, delete) statements for data [add, delete, modify, query statements] 2. Data Definition Language DDL (Data Definition Language): includes statements for database. Create, delete, modify statements 3. Data Control Language DCL (Data Control Language): including .

8. [Mysql] How long does it take to modify the table structure and add a value to an enum field in a table with 10 million records?

Introduction: Mysql5.5 table is InnoDB, the field is named type, which is a normal field and is not included in any index/primary key. The type field originally had two values ​​'a', 'b', and now I want to add the value 'c' to it, so I have a modification statement: {code...} I now want to know how to execute the above statement. ..

##9. Summary of normalized SQL data modification statements_MySQL

Introduction: Normalized SQL data modification Statement summary

10. How to prevent JavaScript from automatically inserting semicolons_javascript tips

Introduction: JavaScript language has a Mechanism: During parsing, a semicolon can be automatically inserted after a sentence to modify the missing semicolon separator at the end of the sentence. However, because this automatically inserted semicolon conflicts with another mechanism of the JavaScript language, that is, all whitespace characters are ignored, so the program can use whitespace to format the code

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