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09-Apr-2020 16:52

Typically, you want to change a subset of records in your tables and not all records.The error can be catastrophic for your data if you don't have a backup.Which rows is to be update, it is decided by a condition. The UPDATE statement can be written in following form: My SQL SYNTAX: If you want to UPDATE with SELECT in My SQL, you can use this syntax: Let's take an example having two tables.Here, First table contains - Cat_id, cat_name, And the second table contains - Rel_cat_id, rel_cat_name SQL UPDATE COLUMN: We can update a single or multiple columns in SQL with SQL UPDATE query.You might want to update all records in your table, but for most circumstances, you use a WHERE clause.The following UPDATE statement template has a WHERE clause: UPDATE The first line of code is the UPDATE statement keyword and then the table you want to edit.Just like the SELECT statement, you need to specify columns and a table, but the UPDATE statement also requires the new data you want to store.

Just like the SELECT statement, string and date values should be encased in single quotes. If you misspell a column name, SQL throws you an error.Because of this indeterminacy, referencing other tables only within sub-selects is safer, though often harder to read and slower than using a join.