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This article is about how to use where conditional queries in mysql. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

-- where sentence

-- Delete users whose ID value is greater than 10

DELETE FROM register WHERE ID > 10

Delete users whose mobile number is not 18900000003

DELETE FROM register WHERE telemetry 18900000003umbent-weak syntax, this value can be used as a number or a string

-- AND OR: join multiple conditions

-- Delete id=5 or mobile number = 18900000005 user

DELETE FROM register where id=5 or tel=18900000005

-- delete id 10 and mobile number 189000011

DELETE FROM regist where id=10 AND tel=18900000011

DELETE FROM regist where id=10 AND tel=18900000010

-- modify all records

-- change the initial funds to 10000

UPDATE register SET fund=10000

-modify the record of the specified condition

UPDATE register SET fund=0 where id=1

-- AND OR

UPDATE register SET fund=0,tel=13777777777 where id=2

-- query all records and display all field values

Select * from register;-- * has some performance problems

-- query all records and display the specified field values

Select name,age,fund,tel from register

-- query users whose balance is greater than 2w, and display their name, balance information and mobile phone number

Select name,fund,tel from register where fund > 20000

-- Delete all records in the table

DELETE FROM register

-- clear the table to clear the self-growth value

Truncate table register

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