In MySQL, is there a way to drop every field in my table, short of using:
ALTER TABLE `table`
DROP COLUMN d1,
DROP COLUMN d1,
etc....
Almost like TRUNCATE for fields maybe?
You'll get an error when you try to drop the last column:
ERROR 1090 (42000): You can't delete all columns with ALTER TABLE; use DROP TABLE instead
Says it all! There's no way to have a table with zero columns.
DROP TABLE table
Related
I am trying to rename a column in MySQL community server 5.5.27 using this SQL expression:
ALTER TABLE table_name RENAME COLUMN old_col_name TO new_col_name;
I also tried
ALTER TABLE table_name RENAME old_col_name TO new_col_name;
But it says:
Error: check the Manual that corresponds to your MySQL server version
Use the following query:
ALTER TABLE tableName CHANGE oldcolname newcolname datatype(length);
The RENAME function is used in Oracle databases.
ALTER TABLE tableName RENAME COLUMN oldcolname TO newcolname datatype(length);
#lad2025 mentions it below, but I thought it'd be nice to add what he said. Thank you #lad2025!
You can use the RENAME COLUMN in MySQL 8.0 to rename any column you need renamed.
ALTER TABLE table_name RENAME COLUMN old_col_name TO new_col_name;
ALTER TABLE Syntax:
RENAME COLUMN:
Can change a column name but not its definition.
More convenient than CHANGE to rename a column without changing its definition.
In Server version: 5.6.34 MySQL Community Server
ALTER TABLE table_name
CHANGE COLUMN old_column_name new_column_name data_type;
From MySQL 5.7 Reference Manual.
Syntax :
ALTER TABLE t1 CHANGE a b DATATYPE;
e.g. : for Customer TABLE having COLUMN customer_name, customer_street, customercity.
And we want to change customercity TO customer_city :
alter table customer change customercity customer_city VARCHAR(225);
From MySQL 8.0 you could use
ALTER TABLE table_name RENAME COLUMN old_col_name TO new_col_name;
ALTER TABLE Syntax:
RENAME COLUMN:
Can change a column name but not its definition.
More convenient than CHANGE to rename a column without changing its definition.
DBFiddle Demo
You can use following code:
ALTER TABLE `dbName`.`tableName` CHANGE COLUMN `old_columnName` `new_columnName` VARCHAR(45) NULL DEFAULT NULL ;
ALTER TABLE `table_name` CHANGE `$old_column_name` `new_column_name` VARCHAR(40)
this is working for me
Changing name in MySQL we have to use "ALTER" table command followed by "CHANGE". Below is the query.
ALTER TABLE tablename CHANGE COLUMN oldcolname newcolname datatype;
ALTER TABLE tablename CHANGE oldcolname newcolname datatype;
PS- You can add "COLUMN" word or ignore in the query. It will work same.
"RENAME" is used in Oracle database.
ALTER TABLE table_name CHANGE old_column_name new_column_name columnDataType;
Rename column name in mysql
alter table categories change type category_type varchar(255);
In mysql your query should be like
ALTER TABLE table_name change column_1 column_2 Data_Type;
you have written the query in Oracle.
Syntax: ALTER TABLE table_name CHANGE old_column_name new_column_name datatype;
If table name is Student and column name is Name.
Then, if you want to change Name to First_Name
ALTER TABLE Student CHANGE Name First_Name varchar(20);
https://dev.mysql.com/doc/refman/8.0/en/alter-table.html
For MySQL 8
alter table creditReportXml_temp change column applicationID applicantID int(11);
for mysql version 5
alter table *table_name* change column *old_column_name* *new_column_name* datatype();
Rename MySQL Column with ALTER TABLE Command
ALTER TABLE is an essential command used to change the structure of a MySQL table. You can use it to add or delete columns, change the type of data within the columns, and even rename entire databases. The function that concerns us the most is how to utilize ALTER TABLE to rename a column.
Clauses give us additional control over the renaming process. The RENAME COLUMN and CHANGE clause both allow for the names of existing columns to be altered. The difference is that the CHANGE clause can also be used to alter the data types of a column. The commands are straightforward, and you may use the clause that fits your requirements best.
How to Use the RENAME COLUMN Clause (MySQL 8.0)
The simplest way to rename a column is to use the ALTER TABLE command with the RENAME COLUMN clause. This clause is available since MySQL version 8.0.
Let’s illustrate its simple syntax. To change a column name, enter the following statement in your MySQL shell:
ALTER TABLE your_table_name RENAME COLUMN original_column_name TO new_column_name;
Exchange the your_table_name, original_column_name, and new_column_name with your table and column names. Keep in mind that you cannot rename a column to a name that already exists in the table.
Note: The word COLUMN is obligatory for the ALTER TABLE RENAME COLUMN command. ALTER TABLE RENAME is the existing syntax to rename the entire table.
The RENAME COLUMN clause can only be used to rename a column. If you need additional functions, such as changing the data definition, or position of a column, you need to use the CHANGE clause instead.
Rename MySQL Column with CHANGE Clause
The CHANGE clause offers important additions to the renaming process. It can be used to rename a column and change the data type of that column with the same command.
Enter the following command in your MySQL client shell to change the name of the column and its definition:
ALTER TABLE your_table_name CHANGE original_column_name new_col_name data_type;
The data_type element is mandatory, even if you want to keep the existing datatype.
Use additional options to further manipulate table columns. The CHANGE also allows you to place the column in a different position in the table by using the optional FIRST | AFTER column_name clause. For example:
ALTER TABLE your_table_name CHANGE original_column_name new_col_name y_data_type AFTER column_x;
You have successfully changed the name of the column, changed the data type to y_data_type, and positioned the column after column_x.
For MySQL <= 8
ALTER TABLE table_names CHANGE `old_column_name` `new_column_name` varchar(50);
Posting it here, it helps helps else ignore it but when trying to use the Change Column and Rename column functions it is throwing me an error.
So figured I would see what statement is generated when we go ahead and rename the column by going into table properties. Below is the command been generated.
EXEC DB.sys.sp_rename N'db.tablename.TrackingIDChargeDescription1' , N'ChargeDescription1', 'COLUMN';
I used and renamed bunch of columns in table.
None of the above worked when I had a column with parenthesis.
Then I tried ` and the magic worked. So if you have a special character in your column by mistake and you want to rename it, use ` for the name of the existing column. For example:
ALTER TABLE table_name RENAME COLUMN column(old) TO new_column;
if you are using gui SQL SMS
you can do db -> Tables -> Table -> columns -> column you want to rename
right click and rename
I am trying to rename a column in MySQL community server 5.5.27 using this SQL expression:
ALTER TABLE table_name RENAME COLUMN old_col_name TO new_col_name;
I also tried
ALTER TABLE table_name RENAME old_col_name TO new_col_name;
But it says:
Error: check the Manual that corresponds to your MySQL server version
Use the following query:
ALTER TABLE tableName CHANGE oldcolname newcolname datatype(length);
The RENAME function is used in Oracle databases.
ALTER TABLE tableName RENAME COLUMN oldcolname TO newcolname datatype(length);
#lad2025 mentions it below, but I thought it'd be nice to add what he said. Thank you #lad2025!
You can use the RENAME COLUMN in MySQL 8.0 to rename any column you need renamed.
ALTER TABLE table_name RENAME COLUMN old_col_name TO new_col_name;
ALTER TABLE Syntax:
RENAME COLUMN:
Can change a column name but not its definition.
More convenient than CHANGE to rename a column without changing its definition.
In Server version: 5.6.34 MySQL Community Server
ALTER TABLE table_name
CHANGE COLUMN old_column_name new_column_name data_type;
From MySQL 5.7 Reference Manual.
Syntax :
ALTER TABLE t1 CHANGE a b DATATYPE;
e.g. : for Customer TABLE having COLUMN customer_name, customer_street, customercity.
And we want to change customercity TO customer_city :
alter table customer change customercity customer_city VARCHAR(225);
From MySQL 8.0 you could use
ALTER TABLE table_name RENAME COLUMN old_col_name TO new_col_name;
ALTER TABLE Syntax:
RENAME COLUMN:
Can change a column name but not its definition.
More convenient than CHANGE to rename a column without changing its definition.
DBFiddle Demo
You can use following code:
ALTER TABLE `dbName`.`tableName` CHANGE COLUMN `old_columnName` `new_columnName` VARCHAR(45) NULL DEFAULT NULL ;
ALTER TABLE `table_name` CHANGE `$old_column_name` `new_column_name` VARCHAR(40)
this is working for me
Changing name in MySQL we have to use "ALTER" table command followed by "CHANGE". Below is the query.
ALTER TABLE tablename CHANGE COLUMN oldcolname newcolname datatype;
ALTER TABLE tablename CHANGE oldcolname newcolname datatype;
PS- You can add "COLUMN" word or ignore in the query. It will work same.
"RENAME" is used in Oracle database.
ALTER TABLE table_name CHANGE old_column_name new_column_name columnDataType;
Rename column name in mysql
alter table categories change type category_type varchar(255);
In mysql your query should be like
ALTER TABLE table_name change column_1 column_2 Data_Type;
you have written the query in Oracle.
Syntax: ALTER TABLE table_name CHANGE old_column_name new_column_name datatype;
If table name is Student and column name is Name.
Then, if you want to change Name to First_Name
ALTER TABLE Student CHANGE Name First_Name varchar(20);
https://dev.mysql.com/doc/refman/8.0/en/alter-table.html
For MySQL 8
alter table creditReportXml_temp change column applicationID applicantID int(11);
for mysql version 5
alter table *table_name* change column *old_column_name* *new_column_name* datatype();
Rename MySQL Column with ALTER TABLE Command
ALTER TABLE is an essential command used to change the structure of a MySQL table. You can use it to add or delete columns, change the type of data within the columns, and even rename entire databases. The function that concerns us the most is how to utilize ALTER TABLE to rename a column.
Clauses give us additional control over the renaming process. The RENAME COLUMN and CHANGE clause both allow for the names of existing columns to be altered. The difference is that the CHANGE clause can also be used to alter the data types of a column. The commands are straightforward, and you may use the clause that fits your requirements best.
How to Use the RENAME COLUMN Clause (MySQL 8.0)
The simplest way to rename a column is to use the ALTER TABLE command with the RENAME COLUMN clause. This clause is available since MySQL version 8.0.
Let’s illustrate its simple syntax. To change a column name, enter the following statement in your MySQL shell:
ALTER TABLE your_table_name RENAME COLUMN original_column_name TO new_column_name;
Exchange the your_table_name, original_column_name, and new_column_name with your table and column names. Keep in mind that you cannot rename a column to a name that already exists in the table.
Note: The word COLUMN is obligatory for the ALTER TABLE RENAME COLUMN command. ALTER TABLE RENAME is the existing syntax to rename the entire table.
The RENAME COLUMN clause can only be used to rename a column. If you need additional functions, such as changing the data definition, or position of a column, you need to use the CHANGE clause instead.
Rename MySQL Column with CHANGE Clause
The CHANGE clause offers important additions to the renaming process. It can be used to rename a column and change the data type of that column with the same command.
Enter the following command in your MySQL client shell to change the name of the column and its definition:
ALTER TABLE your_table_name CHANGE original_column_name new_col_name data_type;
The data_type element is mandatory, even if you want to keep the existing datatype.
Use additional options to further manipulate table columns. The CHANGE also allows you to place the column in a different position in the table by using the optional FIRST | AFTER column_name clause. For example:
ALTER TABLE your_table_name CHANGE original_column_name new_col_name y_data_type AFTER column_x;
You have successfully changed the name of the column, changed the data type to y_data_type, and positioned the column after column_x.
For MySQL <= 8
ALTER TABLE table_names CHANGE `old_column_name` `new_column_name` varchar(50);
Posting it here, it helps helps else ignore it but when trying to use the Change Column and Rename column functions it is throwing me an error.
So figured I would see what statement is generated when we go ahead and rename the column by going into table properties. Below is the command been generated.
EXEC DB.sys.sp_rename N'db.tablename.TrackingIDChargeDescription1' , N'ChargeDescription1', 'COLUMN';
I used and renamed bunch of columns in table.
None of the above worked when I had a column with parenthesis.
Then I tried ` and the magic worked. So if you have a special character in your column by mistake and you want to rename it, use ` for the name of the existing column. For example:
ALTER TABLE table_name RENAME COLUMN column(old) TO new_column;
if you are using gui SQL SMS
you can do db -> Tables -> Table -> columns -> column you want to rename
right click and rename
I want to truncate table but when column value equals NULL
truncate table FB_Player where FB_Player.Status ='NULL'
You can not Use Where Clause with truncate. Truncate clears all the data from a table without any condition. Instead you use Delete command.
You are looking for Delete not Truncate.
You cannot use where clause with TRUNCATE.
You can try this:-
delete from FB_Player where FB_Player.Status is NULL
From wiki
You cannot specify a WHERE clause in a TRUNCATE TABLE statement—it is
all or nothing.
Am using the below code to create an EVENT in MYSQL. In this time i want to drop and create a table using a query.
Drop Event if exists EVT_UP_TIMESHEET;
CREATE EVENT EVT_UP_TIMESHEET
ON SCHEDULE EVERY '1' Day
STARTS '2012-08-01 12:00:00'
DO
Drop table if exists tbl_temp;
create table tbl_temp as ( SELECT e.userid AS Employee_ID,
e.memo AS Employee_Name,
e.Department AS Department,
.....
It returns the following error:
ERROR : Table tbl_temp already exists.
Please help me to do this.
Use CREATE TABLE IF NOT EXISTS tbl_temp instead of create table tbl_temp
Or to delete the table you can use TRUNCATE TABLE instead of DROP TABLE and to create you can use INSERT...SELECT instead of CREATE TABLE.
As a workaround - try to use TRUNCATE TABLE and INSERT...SELECT statements instead of DROP/CREATE TABLE.
I simply want to drop the table 'whatever' if it exist and then recreate table 'whatever' in a single query if possible.
DROP TABLE IF EXISTS `whatever` ELSE
CREATE TABLE `whatever`
Any idea ?
CREATE TABLE `whatever` IF NOT EXISTS ELSE TRUNCATE `whatever`
Use TRUNCATE to empty the table and reset cardinality instead of deleting the table and recreating it.