Update a value in a database field!!!

This can be done in oracle with the following statement:

select replace(replace(bookname,'1001',''),'1002','') from test ;

Use the replace() function.

replace('string','s1','s2'string The character or variable you want to be replaced.

s1 The string that was replaced.

s2 The string to replace.

Idea: Replaced with an empty string'1001','1002'

If you want to really delete it, you can directly use update to change it:

update test set bookname=replace(replace(bookname,'1001',''),'1002','');

Delete rows with values of 1001 or 1002.

delete from test

where bookename like '%1001%' or bokname like '%1002%'

Delete rows that have values of both 1001 and 1002.

delete from test

where bookname like'%1001%1002%' or bookname like'%1002%1001%'

You can use the update method directly in SQL.

sql：update table tablename set name ='zhangsan'；

Explanation: The above SQL means that the value of the name field in the tablename table is updated to "Zhang San".

update [table name] set [field name] = [value] where [condition].

update table set the field you want to update = the value you want to update where you want to update the condition.

You write like this complicated, change to.

update

set dtzc =

from select dtzc b1

zkzh b2

from bwhere zkzh =

Use the update statement. The syntax is: update table name set column = value[, colunm = value....where condition];

The part in indicates that there may or may not be there.

For example: update students set stu name ="zhangsan", stu_gender = "m" where stu_id = 5;

Format: update table name set field name = field name + 1 [ where statement].

For example, if there is a student table in the database, you want to add 1 to the score of a student with an ID of 1.

update student set score=score+1 where id = 1

If you don't add where the system won't know which record you want to update, the score will increase by 1 in all of the tables, unless, of course, that's what you intended.

Format: update table name.

Baidu set Field name = field name + 1 [ where statement zhi] For example, if there is a student table in the database, if you want to add 1 to the student's score with ID 1, then update student set score=score+1 where id = 1 If you don't add where to the right, the system won't know which record you want to update, resulting in the score in all the tables increasing by 1. Unless, of course, that's what you intended.

Remember to adopt it.

1. Create table test replace(id number, value varchar2(20));

2. Insert test data.

insert into test_replace values(1,'1yy');

insert into test_replace values(2,'1yy');

insert into test_replace values(3,'2xx');

insert into test_replace values(4,'3ss');

insert into test_replace values(5,'4bbb');

3. Query the number of all records in the table, select t*,rowid from test replace t,4、Write sql,implement the replacement function,select t.*,replace(value,'1yy','1y') value2 from test_replace t，

If your database is access, you can't do it.

SQL Server.

update a set x = replace(x,'a','b');

Hypothesis: The original content of x is abababab

After execution, it becomes bbbbbbbb

like ''60__c%''Add the percent sign and try again.

update table set field=replace(field,'Haidian District','Chaoyang District')

where 。。Such?

Check it out first, and then use the string replace method to update the updated string into the database.

update table name set a=replace( a,'Haidian', 'Rising sun') where a like 'Haidian';