Sql updating a table from another table christian dating milestones


Unlike the Find and Replace dialog box, an update query lets you: As a best practice when creating an update query, first create a select query that identifies the records that you want to update, and then convert that query to an update query that you can run to update the records.

By selecting data first, you can verify that you’re updating the records you want before you actually change any data.

sql updating a table from another table-57

Sql updating a table from another table

You can think of update queries as a powerful form of the Find and Replace dialog box.

You cannot use an update query to add new records to a database, or to delete records from a database.

UPDATE My Table SET Column1 = (SELECT Some Column FROM Some Other Table WHERE Such And Such = This And That), Column2 = (SELECT Some Other Column FROM Some Other Table WHERE Such And Such = This And That), ... FROM My Table INNER JOIN Some Other Table ON My Table. This And That WHERE Primary Key Column = Some Value Bear in mind that updating data in one table with data from another table may be a sign of bad database design.

WHERE Primary Key Column = Some Value UPDATE My Table SET Column1 = Some Other Table. I've seen developers use these approaches to duplicate data across multiple tables so that it's "easier" or "quicker" to write a query to read the data, but such actions are (usually) folly.

As a result, some of the data in the destination fields may be truncated (deleted).