ALTER USER myuser WITH SUPERUSER;
Here is what the above code is Doing:
1. Create a new user named myuser with password mypass.
2. Give myuser permission to create databases and tables.
3. Give myuser permission to create new roles.
4. Make myuser a superuser so that it can do anything.
DELETE * FROM table_name; Here is what the above code is Doing: 1. We’re selecting all the rows from the table. 2. We’re deleting all the rows from the table.
— CREATE TEMP TABLE Create Table #MyTempTable ( EmployeeID int ); Here is what the above code is Doing: 1. Create a temp table called #MyTempTable 2. Insert the EmployeeID’s from the Employee table into the temp table 3. Select the EmployeeID’s from the temp table 4. Drop the temp table
SELECT cons.OWNER AS CHILD_OWNER, cons.TABLE_NAME AS CHILD_TABLE, cons.CONSTRAINT_NAME AS CONSTAINT_NAME, cons.CONSTRAINT_TYPE AS CONSTRAINT_TYPE, col.OWNER AS PARENT_OWNER, col.TABLE_NAME AS PARENT_TABLE, col.COLUMN_NAME AS COLUMN_NAME FROM DBA_CONS_COLUMNS col, DBA_CONSTRAINTS cons WHERE cons.R_OWNER = col.OWNER AND cons.R_CONSTRAINT_NAME = col.CONSTRAINT_NAME AND cons.TABLE_NAME = ‘table_name’; Here is what the above code is Doing: 1. We’re selecting the owner of the child…
SELECT * FROM SYS.DATABASES Here is what the above code is Doing: 1. Create a connection to the database 2. Create a cursor object 3. Execute the query 4. Fetch the results 5. Close the connection
DELETE FROM CONTACTS WHERE ID NOT IN (SELECT * FROM (SELECT max(ID) FROM CONTACTS GROUP BY EMAIL) t); — ⇓ Test it ⇓ (Fiddle source link) Here is what the above code is Doing: 1. The innermost query is selecting the maximum ID for each email. 2. The next query is selecting all the rows…
DECLARE @strvalue varchar(20) = ‘SDADH/SDKDS/SD/UIO-123/WEA/456’ SELECT REVERSE(SUBSTRING(REVERSE(@strvalue),0,CHARINDEX (‘/’,REVERSE(@strvalue)))) Here is what the above code is Doing: 1. Reverse the string 2. Find the first occurrence of ‘/’ 3. Take the substring from the beginning of the string to the first occurrence of ‘/’ 4. Reverse the string again