The update statement is used to update or change records that match a specified criteria. This is accomplished by carefully constructing a where clause. update "tablename"set "columnname" = "newvalue" [,"nextcolumn" = "newvalue2"...]where "columnname" OPERATOR "value" [and|or "column" OPERATOR "value"]; [The above example was line wrapped for better viewing on this Web page.] update phone_book set area_code = 623 where prefix = 979;update phone_book set last_name = 'Smith', prefix=555, suffix=9292 where last_name = 'Jones';update employee set age = age+1 where first_name='Mary' and last_name='Williams'; After each update, issue a select statement to verify your changes. Jonie Weber just got married to Bob Williams. She has requested that her last name be updated to Weber-Williams. Dirk Smith's birthday is today, add 1 to his age. All secretaries are now called "Administrative Assistant". Update all titles accordingly. Everyone that's making under 30000 are to receive a 3500 a year raise.
Everyone that's making over 33500 are to receive a 4500 a year raise. All "Programmer II" titles are now promoted to "Programmer III". All "Programmer" titles are now promoted to "Programmer II". Create at least 5 of your own update statements and submit them.The PostgreSQL UPDATE Query is used to modify the existing records in a table. You can use WHERE clause with UPDATE query to update selected rows otherwise all the rows would be updated. The basic syntax of UPDATE query with WHERE clause is as follows: You can combine N number of conditions using AND or OR operators. Consider the table COMPANY having records as follows: Following is an example which would update ADDRESS for a customer, whose ID is 6: Now, COMPANY table would have the following records: If you want to modify all ADDRESS and SALARY column values in COMPANY table, you do not need to use WHERE clause and UPDATE query would be as follows: Now, COMPANY table will have the following records:
Home → Documentation → Manuals → PostgreSQL 8.2 This page in other versions: NameUPDATE -- update rows of a table UPDATE changes the values of the specified columns in all rows that satisfy the condition. the columns to be modified need be mentioned in the SET clause; columns not explicitly modified retain By default, UPDATE will update rows in the specified table and all its subtables. If you wish to only update the specific table mentioned, you must use the ONLY clause. There are two ways to modify a table using information contained in other tables in the database: using sub-selects, or specifying additional tables in the FROMWhich technique is more appropriate depends on the The optional RETURNING clause causes UPDATE to compute and return value(s) based on each row actually updated. Any expression using the table's columns, and/or columns of other tables mentioned in FROM, can be computed. (post-update) values of the table's columns are used.
of the RETURNING list is identical to that of the output list of SELECT. You must have the UPDATE privilege on the table to update it, as well as the SELECT privilege to any table whose values are read in the expressions or The name (optionally schema-qualified) of the table to A substitute name for the target table. When an alias is provided, it completely hides the actual name of the table. For example, given UPDATE foo AS f, the remainder of the UPDATE statement must refer to this table as The name of a column in table. The column name can be qualified with a subfield name or array subscript, ifDo not include the table's name in the specification of a target column — for example, UPDATE tab SET tab.col = 1 is invalid. An expression to assign to the column. may use the old values of this and other columns in the Set the column to its default value (which will be NULL if no specific default expression has been assigned to
A list of table expressions, allowing columns from other tables to appear in the WHERE condition and the update expressions. This is similar to the list of tables that can be specified in the FROM Clause of a target table must not appear in the fromlist, unless you intend a self-join (in which case it must appear with an alias in An expression that returns a value of type boolean. Only rows for which this expression returns true will be updated. An expression to be computed and returned by the UPDATE command after each row isThe expression may use any column names of the table or table(s) listed inWrite * to return all columns. A name to use for a returned column. On successful completion, an UPDATE command returns a command tag of the form The count is the number ofIf count is 0, no rows matched the condition (this is not considered an error). If the UPDATE command contains a RETURNING clause, the result will be
similar to that of a SELECT statement containing the columns and values defined in the RETURNING list, computed over the row(s) updated When a FROM clause is present, what essentially happens is that the target table is joined to the tables mentioned in the fromlist, and each output row of the join represents an update operation for the target table. you should ensure that the join produces at most one output row for each row to be modified. In other words, a target row shouldn't join to more than one row from the other table(s). it does, then only one of the join rows will be used to update the target row, but which one will be used is not readily Because of this indeterminacy, referencing other tables only within sub-selects is safer, though often harder to read and slower than using a join. Change the word Drama to Dramatic in the column kind of the table films: Adjust temperature entries and reset precipitation to its
default value in one row of the table weather: Perform the same operation and return the updated entries: Use the alternative column-list syntax to do the same Increment the sales count of the salesperson who manages the account for Acme Corporation, using the FROM clause syntax: Perform the same operation, using a sub-select in the Attempt to insert a new stock item along with the quantity ofIf the item already exists, instead update the stock count of the existing item. To do this without failing the entire This command conforms to the SQL standard, except that the FROM and RETURNING According to the standard, the column-list syntax should allow a list of columns to be assigned from a single row-valued expression, such as a sub-select: This is not currently implemented — the source must be a list Some other database systems offer a FROM option in which the target table is supposed to be listed again within FROM.