How to rename a table in SQLite 3.0?
ALTER TABLE `foo` RENAME TO `bar` SQLite Query Language: ALTER TABLE
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SQL-script: How to write ALTER statements to set Primary key on an existing table?
drop constraint and recreate it alter table Persion drop CONSTRAINT <constraint_name> alter table Persion add primary key (persionId,Pname,PMID) edit: you can find the constraint name by using the query below: select OBJECT_NAME(OBJECT_ID) AS NameofConstraint FROM sys.objects where OBJECT_NAME(parent_object_id)=’Persion’ and type_desc LIKE ‘%CONSTRAINT’
How to UPSERT (update or insert into a table?)
The MERGE statement merges data between two tables. Using DUAL allows us to use this command. Note that this is not protected against concurrent access. create or replace procedure ups(xa number) as begin merge into mergetest m using dual on (a = xa) when not matched then insert (a,b) values (xa,1) when matched then update … Read more
How to insert multiple rows in SQLite?
update As BrianCampbell points out here, SQLite 3.7.11 and above now supports the simpler syntax of the original post. However, the approach shown is still appropriate if you want maximum compatibility across legacy databases. original answer If I had privileges, I would bump river’s reply: You can insert multiple rows in SQLite, you just need … Read more
MySQL: Count records from one table and then update another
Use a subquery: UPDATE nations SET count = ( SELECT COUNT(id) FROM poets WHERE poets.nation = nations.id GROUP BY id );
How do I add a column to large sql server table
ALTER TABLE table1 ADD newcolumn int NULL GO should not take that long… What takes a long time is to insert columns in the middle of other columns… b/c then the engine needs to create a new table and copy the data to the new table.
Adding current date time in SQL Table using SSMS Edit Mode
Here’s something fairly quick and easy. In a new query window execute the query, SELECT GETDATE(). Select the result in the result pane and ctrl-c to copy it to the clipboard. Then go back to your Edit window, and paste into the datetime cell(s).
Using Encrypt=yes in a Sql Server connection string -> “provider: SSL Provider, error: 0 – The certificate’s CN name does not match the passed value.”
Your database connection can be configured to encrypt traffic and to accept any certificate from your server. Not a grand solution, but it worked for me. The resulting connection string should look like this: “[…];Encrypt=True;TrustServerCertificate=True”
How to count unique rows in Oracle
How about SELECT COUNT(*) FROM (SELECT DISTINCT * FROM Table)
Spark – Group by HAVING with dataframe syntax?
Yes, it doesn’t exist. You express the same logic with agg followed by where: df.groupBy(someExpr).agg(somAgg).where(somePredicate)