What is comment command in SQL?
Comments are used to explain sections of SQL statements, or to prevent execution of SQL statements. Note: The examples in this chapter will not work in Firefox and Microsoft Edge! Comments are not supported in Microsoft Access databases. Firefox and Microsoft Edge are using Microsoft Access database in our examples.
How do I comment in SQL query?
Comments
- Begin the comment with a slash and an asterisk (/*). Proceed with the text of the comment. This text can span multiple lines. End the comment with an asterisk and a slash (*/).
- Begin the comment with — (two hyphens). Proceed with the text of the comment. This text cannot extend to a new line.
How do I comment a query in Pgadmin?
Ctrl k will comment out a block of code, while Ctrl-Shift k will uncomment out the block.
How do I see comments on a column in SQL?
You can view the comments on a particular table or column by querying the data dictionary views USER_TAB_COMMENTS , DBA_TAB_COMMENTS , or ALL_TAB_COMMENTS or USER_COL_COMMENTS , DBA_COL_COMMENTS , or ALL_COL_COMMENTS .
How do I edit a table in PostgreSQL?
The syntax to modify a column in a table in PostgreSQL (using the ALTER TABLE statement) is: ALTER TABLE table_name ALTER COLUMN column_name TYPE column_definition; table_name. The name of the table to modify.
How do I write a query in PostgreSQL Pgadmin 4?
The SQL Editor Panel¶ For example, type “SELECT * FROM” (without quotes, but with a trailing space), and then press the Control+Space key combination to select from a popup menu of autocomplete options. After entering a query, select the Execute/Refresh icon from the toolbar.
How do I see comments in a table in SQL Server?
SQL command to list all tables in Oracle
- Show all tables owned by the current user: SELECT table_name FROM user_tables;
- Show all tables in the current database: SELECT table_name FROM dba_tables;
- Show all tables that are accessible by the current user:
How do I comment in a stored procedure?
COMMENT ON PROCEDURE customer() IS ‘Author: bsmith Version: 1.0 Description: A procedure that writes a customer name to the database log file. ‘; To comment on a stored procedure, you must either be the Netezza admin user, the owner of the procedure, or you must have Alter permissions for procedure objects.
What are inline comments?
Inline comments are comments made by an instructor that appear directly on top of your paper. These comments are usually brief.
What is Alter command in PostgreSQL?
The PostgreSQL ALTER TABLE command is used to add, delete or modify columns in an existing table. You would also use ALTER TABLE command to add and drop various constraints on an existing table.
How do I alter a column in PostgreSQL?
First, specify the name of the table to which the column you want to change belongs in the ALTER TABLE clause. Second, give the name of column whose data type will be changed in the ALTER COLUMN clause. Third, provide the new data type for the column after the TYPE keyword.