How to modify column names in a table with ALTERTABLE statement in SQL?
1. altertablestudent_infoadd “Student Name” varchar(10);
2. updatestudent_infoset “Student Name ” = ‘Name’;
3. altertablestudent_infodropcolumn “Name”.
SQL language, short for Structured Query Language (Structured Query Language).SQL language is a database query and programming language for accessing data as well as querying, updating, and managing relational database systems; it is also the extension for database script files.
How to write a standard sql statement to modify a column name in a data table?
The modification of the column name of the various databases are supported by the writing in the end there is, I’m not quite sure.x0a Below are three databases of their respective write-ups.x0aYou can switch to test test to see which write-ups are supported by various databases.x0ax0aOraclex0aSQL>ALTERTABLEtest_tabx0a2RENAMECOLUMNvalTOval2;x0aTablealtered. tabx0a2RENAMECOLUMNvalTOval2;x0aTablealtered.x0ax0aSQLServerx0a call EXECUTEsp_rename to make changes to the database table, column names.x0a1>EXECUTEsp_renameN’dbo. test_tab.val’,N’Tmp_val2′,’COLUMN’x0a2>GOx0aNote: Changing any part of the object name can break scripts and stored procedures. x0a1>EXECUTEsp_renameN’dbo.test_tab. ,’COLUMN’x0a2>GOx0a Note: Changing any part of the object name may break scripts and stored procedures.x0ax0aMySQLx0amysql>ALTERTABLEtest_tabx0a->CHANGECOLUMNvalval2VARCHAR(10);/ /x0aQueryOK,0rowsaffected(0.13sec)x0aRecords:0Duplicates:0Warnings:0
sql modify statement
Using UPDATE statement in SQL to modify data in table.
The sql modify statement is written as [UPDATE table name SET column name = new value WHERE column name = some value].
The UPDATE statement specifies not only the rows to be changed, but also the expression to be used as the new value for a particular column in those rows.
You can use the UPDATE statement to change a single row, a group of rows, or all rows in a table. Unlike other data modification statements (INSERT, MERGE, and DELETE), the UPDATE statement can also modify rows in multiple tables at the same time.
In all cases, the execution of the UPDATE statement is atomic; either all rows are modified correctly or none are modified. For example, if the data type of one of the values currently being modified is incorrect, or if the new value causes a CHECK constraint to be violated, the UPDATE will fail and the entire operation will fall back.
Update Statement Usage Considerations
1. Using the Update statement, if you omit the “Where Condition”, you will update all the rows in the data table.
2. When assigning values, pay attention to the type of field. If the text type or note type, the field value on both sides to add quotes, if the date / time type, the field value on both sides to add # (quotes can also be); if the Boolean type, the value of the field True or False; if the automatic numbering type, do not assign a value to the field.