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Editor to share with you how to update the records in the basic table using the sql command how to write, I believe most people do not know much about it, so share this article for your reference, I hope you will learn a lot after reading this article, let's go to know it!

There is only one way to update the database, Update

Its standard format: Update table name set field = value where condition

However, there are differences depending on the source of the data:

1. Import from the outside

This is relatively simple.

Example:

Update tb set UserName= "XXXXX" where UserID= "aasdd"

2. Some internal variables, functions, such as time, etc.

Assign a function directly to a field

Update tb set LastDate=date () where UserID= "aasdd"

3. For some field variables + 1, common ones such as click-through rate, download times, etc.

This directly assigns the field + 1 to itself.

Update tb set clickcount=clickcount+1 where ID=xxx

4. Assign one field of the same record to another field

Update tb set Lastdate= regdate where XXX

5. Update a batch of records from one table to another

Table1

ID f1 f2

Table2

ID f1 f2

First update F1 f2 in table2 to table1 (same ID)

Update table1,table2 set table1.f1=table2.f1,table1.f2=table2.f2 where table1.ID=table2.ID

Update some records from the same table to other records

Table: a

IDmonthE_IDPrice1112212432154225

First, update the February product price in the table to mid-January.

Obviously, to find the same E_ID for ID in mid-February and mid-January and update price to mid-January

This can be handled with the above method, but because of the same table, in order to distinguish between two months, the table should be renamed.

Update a,an as b set a.price=b.price where a.E_ID=b.E_ID and a.month=1 and b.month=2

Of course, you can also query the February query first and update it with the method of 5.

Update a, (select * from a where month=2) as b set a.price=b.price where a.E_ID=b.E_ID and a.month=1 is all the contents of this article entitled "how to write sql commands to update records in the basic table". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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