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2025-04-05 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Database >
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Shulou(Shulou.com)06/01 Report--
Structural operation on the table
Add increase
Alter table table name drop (column character type (length)); delete
Modify reform
Desc dept; look-up table structure
Operation on record
Select column name from table name where condition lookup
Update student set column = "" where condition change
Delete from table name where conditional deletion (only delete records without deleting table structure)
Maximum value of max ()
The minimum value of function min ()
Average of avg ()
Total value of count ()
Associated database query
Select column name, column name from Table 1, Table 2 where Primary key = Foreign key and condition
Select column name, column name from Table 1 where Table 1 Primary key = (select Table 2 Foreign key from
Table 2 where conditions)
What does the like character% begin with
Order by sorting
Group by column name having condition according to what grouping statistics is in use having restriction condition
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