INSERT(7)
NAME
INSERT - create new rows in a table
SYNOPSIS
[ WITH [ RECURSIVE ] with_query [, ...] ]
INSERT INTO table_name [ AS alias ] [ ( column_name [, ...] ) ]
{ DEFAULT VALUES | VALUES ( { expression | DEFAULT } [, ...] ) [, ...] | query }
[ ON CONFLICT [ conflict_target ] conflict_action ]
[ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ]
where conflict_target can be one of:
( { index_column_name | ( index_expression ) } [ COLLATE collation ] [ opclass ] [, ...] ) [ WHERE index_predicate ]
ON CONSTRAINT constraint_name
and conflict_action is one of:
DO NOTHING
DO UPDATE SET { column_name = { expression | DEFAULT } |
( column_name [, ...] ) = ( { expression | DEFAULT } [, ...] ) |
( column_name [, ...] ) = ( sub-SELECT )
} [, ...]
[ WHERE condition ]
DESCRIPTION
INSERT inserts new rows into a table. One can insert one or more rows specified by value expressions, or zero or more rows resulting from a query. The target column names can be listed in any order. If no list of column names is given at all, the default is all the columns of the table in their declared order; or the first N column names, if there are only N columns supplied by the VALUES clause or query. The values supplied by the VALUES clause or query are associated with the explicit or implicit column list left-to-right. Each column not present in the explicit or implicit column list will be filled with a default value, either its declared default value or null if there is none. If the expression for any column is not of the correct data type, automatic type conversion will be attempted. ON CONFLICT can be used to specify an alternative action to raising a unique constraint or exclusion constraint violation error. (See ON CONFLICT Clause below.) The optional RETURNING clause causes INSERT to compute and return value(s) based on each row actually inserted (or updated, if an ON CONFLICT DO UPDATE clause was used). This is primarily useful for obtaining values that were supplied by defaults, such as a serial sequence number. However, any expression using the table's columns is allowed. The syntax of the RETURNING list is identical to that of the output list of SELECT. Only rows that were successfully inserted or updated will be returned. For example, if a row was locked but not updated because an ON CONFLICT DO UPDATE ... WHERE clause condition was not satisfied, the row will not be returned. You must have INSERT privilege on a table in order to insert into it. If ON CONFLICT DO UPDATE is present, UPDATE privilege on the table is also required. If a column list is specified, you only need INSERT privilege on the listed columns. Similarly, when ON CONFLICT DO UPDATE is specified, you only need UPDATE privilege on the column(s) that are listed to be updated. However, ON CONFLICT DO UPDATE also requires SELECT privilege on any column whose values are read in the ON CONFLICT DO UPDATE expressions or condition. Use of the RETURNING clause requires SELECT privilege on all columns mentioned in RETURNING. If you use the query clause to insert rows from a query, you of course need to have SELECT privilege on any table or column used in the query.
PARAMETERS
Inserting
This section covers parameters that may be used when only inserting new
rows. Parameters exclusively used with the ON CONFLICT clause are
described separately.
with_query
The WITH clause allows you to specify one or more subqueries that
can be referenced by name in the INSERT query. See Section 7.8,
"WITH Queries (Common Table Expressions)", in the documentation and
SELECT(7) for details.
It is possible for the query (SELECT statement) to also contain a
WITH clause. In such a case both sets of with_query can be
referenced within the query, but the second one takes precedence
since it is more closely nested.
table_name
The name (optionally schema-qualified) of an existing table.
alias
A substitute name for table_name. When an alias is provided, it
completely hides the actual name of the table. This is particularly
useful when ON CONFLICT DO UPDATE targets a table named excluded,
since that's also the name of the special table representing rows
proposed for insertion.
column_name
The name of a column in the table named by table_name. The column
name can be qualified with a subfield name or array subscript, if
needed. (Inserting into only some fields of a composite column
leaves the other fields null.) When referencing a column with ON
CONFLICT DO UPDATE, do not include the table's name in the
specification of a target column. For example, INSERT INTO
table_name ... ON CONFLICT DO UPDATE SET table_name.col = 1 is
invalid (this follows the general behavior for UPDATE).
DEFAULT VALUES
All columns will be filled with their default values.
expression
An expression or value to assign to the corresponding column.
DEFAULT
The corresponding column will be filled with its default value.
query
A query (SELECT statement) that supplies the rows to be inserted.
Refer to the SELECT(7) statement for a description of the syntax.
output_expression
An expression to be computed and returned by the INSERT command
after each row is inserted or updated. The expression can use any
column names of the table named by table_name. Write * to return
all columns of the inserted or updated row(s).
output_name
A name to use for a returned column.
ON CONFLICT Clause
The optional ON CONFLICT clause specifies an alternative action to
raising a unique violation or exclusion constraint violation error. For
each individual row proposed for insertion, either the insertion
proceeds, or, if an arbiter constraint or index specified by
conflict_target is violated, the alternative conflict_action is taken.
ON CONFLICT DO NOTHING simply avoids inserting a row as its alternative
action. ON CONFLICT DO UPDATE updates the existing row that conflicts
with the row proposed for insertion as its alternative action.
conflict_target can perform unique index inference. When performing
inference, it consists of one or more index_column_name columns and/or
index_expression expressions, and an optional index_predicate. All
table_name unique indexes that, without regard to order, contain
exactly the conflict_target-specified columns/expressions are inferred
(chosen) as arbiter indexes. If an index_predicate is specified, it
must, as a further requirement for inference, satisfy arbiter indexes.
Note that this means a non-partial unique index (a unique index without
a predicate) will be inferred (and thus used by ON CONFLICT) if such an
index satisfying every other criteria is available. If an attempt at
inference is unsuccessful, an error is raised.
ON CONFLICT DO UPDATE guarantees an atomic INSERT or UPDATE outcome;
provided there is no independent error, one of those two outcomes is
guaranteed, even under high concurrency. This is also known as UPSERT ---
"UPDATE or INSERT".
conflict_target
Specifies which conflicts ON CONFLICT takes the alternative action
on by choosing arbiter indexes. Either performs unique index
inference, or names a constraint explicitly. For ON CONFLICT DO
NOTHING, it is optional to specify a conflict_target; when omitted,
conflicts with all usable constraints (and unique indexes) are
handled. For ON CONFLICT DO UPDATE, a conflict_target must be
provided.
conflict_action
conflict_action specifies an alternative ON CONFLICT action. It can
be either DO NOTHING, or a DO UPDATE clause specifying the exact
details of the UPDATE action to be performed in case of a conflict.
The SET and WHERE clauses in ON CONFLICT DO UPDATE have access to
the existing row using the table's name (or an alias), and to rows
proposed for insertion using the special excluded table. SELECT
privilege is required on any column in the target table where
corresponding excluded columns are read.
Note that the effects of all per-row BEFORE INSERT triggers are
reflected in excluded values, since those effects may have
contributed to the row being excluded from insertion.
index_column_name
The name of a table_name column. Used to infer arbiter indexes.
Follows CREATE INDEX format. SELECT privilege on index_column_name
is required.
index_expression
Similar to index_column_name, but used to infer expressions on
table_name columns appearing within index definitions (not simple
columns). Follows CREATE INDEX format. SELECT privilege on any
column appearing within index_expression is required.
collation
When specified, mandates that corresponding index_column_name or
index_expression use a particular collation in order to be matched
during inference. Typically this is omitted, as collations usually
do not affect whether or not a constraint violation occurs. Follows
CREATE INDEX format.
opclass
When specified, mandates that corresponding index_column_name or
index_expression use particular operator class in order to be
matched during inference. Typically this is omitted, as the
equality semantics are often equivalent across a type's operator
classes anyway, or because it's sufficient to trust that the
defined unique indexes have the pertinent definition of equality.
Follows CREATE INDEX format.
index_predicate
Used to allow inference of partial unique indexes. Any indexes that
satisfy the predicate (which need not actually be partial indexes)
can be inferred. Follows CREATE INDEX format. SELECT privilege on
any column appearing within index_predicate is required.
constraint_name
Explicitly specifies an arbiter constraint by name, rather than
inferring a constraint or index.
condition
An expression that returns a value of type boolean. Only rows for
which this expression returns true will be updated, although all
rows will be locked when the ON CONFLICT DO UPDATE action is taken.
Note that condition is evaluated last, after a conflict has been
identified as a candidate to update.
Note that exclusion constraints are not supported as arbiters with ON
CONFLICT DO UPDATE. In all cases, only NOT DEFERRABLE constraints and
unique indexes are supported as arbiters.
INSERT with an ON CONFLICT DO UPDATE clause is a "deterministic"
statement. This means that the command will not be allowed to affect
any single existing row more than once; a cardinality violation error
will be raised when this situation arises. Rows proposed for insertion
should not duplicate each other in terms of attributes constrained by
an arbiter index or constraint.
Tip
It is often preferable to use unique index inference rather than
naming a constraint directly using ON CONFLICT ON CONSTRAINT
constraint_name. Inference will continue to work correctly when
the underlying index is replaced by another more or less equivalent
index in an overlapping way, for example when using CREATE UNIQUE
INDEX ... CONCURRENTLY before dropping the index being replaced.
OUTPUTS
On successful completion, an INSERT command returns a command tag of
the form
INSERT oid count
The count is the number of rows inserted or updated. If count is
exactly one, and the target table has OIDs, then oid is the OID
assigned to the inserted row. The single row must have been inserted
rather than updated. Otherwise oid is zero.
If the INSERT 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) inserted or
updated by the command.
EXAMPLES
Insert a single row into table films:
INSERT INTO films VALUES
('UA502', 'Bananas', 105, '1971-07-13', 'Comedy', '82 minutes');
In this example, the len column is omitted and therefore it will have
the default value:
INSERT INTO films (code, title, did, date_prod, kind)
VALUES ('T_601', 'Yojimbo', 106, '1961-06-16', 'Drama');
This example uses the DEFAULT clause for the date columns rather than
specifying a value:
INSERT INTO films VALUES
('UA502', 'Bananas', 105, DEFAULT, 'Comedy', '82 minutes');
INSERT INTO films (code, title, did, date_prod, kind)
VALUES ('T_601', 'Yojimbo', 106, DEFAULT, 'Drama');
To insert a row consisting entirely of default values:
INSERT INTO films DEFAULT VALUES;
To insert multiple rows using the multirow VALUES syntax:
INSERT INTO films (code, title, did, date_prod, kind) VALUES
('B6717', 'Tampopo', 110, '1985-02-10', 'Comedy'),
('HG120', 'The Dinner Game', 140, DEFAULT, 'Comedy');
This example inserts some rows into table films from a table tmp_films
with the same column layout as films:
INSERT INTO films SELECT * FROM tmp_films WHERE date_prod < '2004-05-07';
This example inserts into array columns:
-- Create an empty 3x3 gameboard for noughts-and-crosses
INSERT INTO tictactoe (game, board[1:3][1:3])
VALUES (1, '{{" "," "," "},{" "," "," "},{" "," "," "}}');
-- The subscripts in the above example aren't really needed
INSERT INTO tictactoe (game, board)
VALUES (2, '{{X," "," "},{" ",O," "},{" ",X," "}}');
Insert a single row into table distributors, returning the sequence
number generated by the DEFAULT clause:
INSERT INTO distributors (did, dname) VALUES (DEFAULT, 'XYZ Widgets')
RETURNING did;
Increment the sales count of the salesperson who manages the account
for Acme Corporation, and record the whole updated row along with
current time in a log table:
WITH upd AS (
UPDATE employees SET sales_count = sales_count + 1 WHERE id =
(SELECT sales_person FROM accounts WHERE name = 'Acme Corporation')
RETURNING *
)
INSERT INTO employees_log SELECT *, current_timestamp FROM upd;
Insert or update new distributors as appropriate. Assumes a unique
index has been defined that constrains values appearing in the did
column. Note that the special excluded table is used to reference
values originally proposed for insertion:
INSERT INTO distributors (did, dname)
VALUES (5, 'Gizmo Transglobal'), (6, 'Associated Computing, Inc')
ON CONFLICT (did) DO UPDATE SET dname = EXCLUDED.dname;
Insert a distributor, or do nothing for rows proposed for insertion
when an existing, excluded row (a row with a matching constrained
column or columns after before row insert triggers fire) exists.
Example assumes a unique index has been defined that constrains values
appearing in the did column:
INSERT INTO distributors (did, dname) VALUES (7, 'Redline GmbH')
ON CONFLICT (did) DO NOTHING;
Insert or update new distributors as appropriate. Example assumes a
unique index has been defined that constrains values appearing in the
did column. WHERE clause is used to limit the rows actually updated
(any existing row not updated will still be locked, though):
-- Don't update existing distributors based in a certain ZIP code
INSERT INTO distributors AS d (did, dname) VALUES (8, 'Anvil Distribution')
ON CONFLICT (did) DO UPDATE
SET dname = EXCLUDED.dname || ' (formerly ' || d.dname || ')'
WHERE d.zipcode <> '21201';
-- Name a constraint directly in the statement (uses associated
-- index to arbitrate taking the DO NOTHING action)
INSERT INTO distributors (did, dname) VALUES (9, 'Antwerp Design')
ON CONFLICT ON CONSTRAINT distributors_pkey DO NOTHING;
Insert new distributor if possible; otherwise DO NOTHING. Example
assumes a unique index has been defined that constrains values
appearing in the did column on a subset of rows where the is_active
Boolean column evaluates to true:
-- This statement could infer a partial unique index on "did"
-- with a predicate of "WHERE is_active", but it could also
-- just use a regular unique constraint on "did"
INSERT INTO distributors (did, dname) VALUES (10, 'Conrad International')
ON CONFLICT (did) WHERE is_active DO NOTHING;
COMPATIBILITY
INSERT conforms to the SQL standard, except that the RETURNING clause is a PostgreSQL extension, as is the ability to use WITH with INSERT, and the ability to specify an alternative action with ON CONFLICT. Also, the case in which a column name list is omitted, but not all the columns are filled from the VALUES clause or query, is disallowed by the standard. Possible limitations of the query clause are documented under SELECT(7).
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