Конструктор запросов
Introduction
Laravel's database query builder provides a convenient, fluent interface to creating and running database queries. It can be used to perform most database operations in your application and works on all supported database systems.
The Laravel query builder uses PDO parameter binding to protect your application against SQL injection attacks. There is no need to clean strings being passed as bindings.
PDO does not support binding column names. Therefore, you should never allow user input to dictate the column names referenced by your queries, including "order by" columns, etc. If you must allow the user to select certain columns to query against, always validate the column names against a white-list of allowed columns.
Retrieving Results
Retrieving All Rows From A Table
You may use the table
method on the DB
facade to begin a query. The table
method returns a fluent query builder instance for the given table, allowing you to chain more constraints onto the query and then finally get the results using the get
method:
The get
method returns an Illuminate\Support\Collection
containing the results where each result is an instance of the PHP stdClass
object. You may access each column's value by accessing the column as a property of the object:
Retrieving A Single Row / Column From A Table
If you just need to retrieve a single row from the database table, you may use the first
method. This method will return a single stdClass
object:
If you don't even need an entire row, you may extract a single value from a record using the value
method. This method will return the value of the column directly:
To retrieve a single row by its id
column value, use the find
method:
Retrieving A List Of Column Values
If you would like to retrieve a Collection containing the values of a single column, you may use the pluck
method. In this example, we'll retrieve a Collection of role titles:
You may also specify a custom key column for the returned Collection:
Chunking Results
If you need to work with thousands of database records, consider using the chunk
method. This method retrieves a small chunk of the results at a time and feeds each chunk into a Closure
for processing. This method is very useful for writing Artisan commands that process thousands of records. For example, let's work with the entire users
table in chunks of 100 records at a time:
You may stop further chunks from being processed by returning false
from the Closure
:
If you are updating database records while chunking results, your chunk results could change in unexpected ways. So, when updating records while chunking, it is always best to use the chunkById
method instead. This method will automatically paginate the results based on the record's primary key:
When updating or deleting records inside the chunk callback, any changes to the primary key or foreign keys could affect the chunk query. This could potentially result in records not being included in the chunked results.
Aggregates
The query builder also provides a variety of aggregate methods such as count
, max
, min
, avg
, and sum
. You may call any of these methods after constructing your query:
You may combine these methods with other clauses:
Determining If Records Exist
Instead of using the count
method to determine if any records exist that match your query's constraints, you may use the exists
and doesntExist
methods:
Selects
Specifying A Select Clause
You may not always want to select all columns from a database table. Using the select
method, you can specify a custom select
clause for the query:
The distinct
method allows you to force the query to return distinct results:
If you already have a query builder instance and you wish to add a column to its existing select clause, you may use the addSelect
method:
Raw Expressions
Sometimes you may need to use a raw expression in a query. To create a raw expression, you may use the DB::raw
method:
Raw statements will be injected into the query as strings, so you should be extremely careful to not create SQL injection vulnerabilities.
Raw Methods
Instead of using DB::raw
, you may also use the following methods to insert a raw expression into various parts of your query.
selectRaw
The selectRaw
method can be used in place of addSelect(DB::raw(...))
. This method accepts an optional array of bindings as its second argument:
whereRaw / orWhereRaw
The whereRaw
and orWhereRaw
methods can be used to inject a raw where
clause into your query. These methods accept an optional array of bindings as their second argument:
havingRaw / orHavingRaw
The havingRaw
and orHavingRaw
methods may be used to set a raw string as the value of the having
clause. These methods accept an optional array of bindings as their second argument:
orderByRaw
The orderByRaw
method may be used to set a raw string as the value of the order by
clause:
groupByRaw
groupByRaw
The groupByRaw
method may be used to set a raw string as the value of the group by
clause:
Joins
Inner Join Clause
The query builder may also be used to write join statements. To perform a basic "inner join", you may use the join
method on a query builder instance. The first argument passed to the join
method is the name of the table you need to join to, while the remaining arguments specify the column constraints for the join. You can even join to multiple tables in a single query:
Left Join / Right Join Clause
If you would like to perform a "left join" or "right join" instead of an "inner join", use the leftJoin
or rightJoin
methods. These methods have the same signature as the join
method:
Cross Join Clause
To perform a "cross join" use the crossJoin
method with the name of the table you wish to cross join to. Cross joins generate a cartesian product between the first table and the joined table:
Advanced Join Clauses
You may also specify more advanced join clauses. To get started, pass a Closure
as the second argument into the join
method. The Closure
will receive a JoinClause
object which allows you to specify constraints on the join
clause:
If you would like to use a "where" style clause on your joins, you may use the where
and orWhere
methods on a join. Instead of comparing two columns, these methods will compare the column against a value:
Subquery Joins
You may use the joinSub
, leftJoinSub
, and rightJoinSub
methods to join a query to a subquery. Each of these methods receive three arguments: the subquery, its table alias, and a Closure that defines the related columns:
Unions
The query builder also provides a quick way to "union" two queries together. For example, you may create an initial query and use the union
method to union it with a second query:
The
unionAll
method is also available and has the same method signature asunion
.
Where Clauses
Simple Where Clauses
You may use the where
method on a query builder instance to add where
clauses to the query. The most basic call to where
requires three arguments. The first argument is the name of the column. The second argument is an operator, which can be any of the database's supported operators. Finally, the third argument is the value to evaluate against the column.
For example, here is a query that verifies the value of the "votes" column is equal to 100:
For convenience, if you want to verify that a column is equal to a given value, you may pass the value directly as the second argument to the where
method:
You may use a variety of other operators when writing a where
clause:
You may also pass an array of conditions to the where
function:
Or Statements
You may chain where constraints together as well as add or
clauses to the query. The orWhere
method accepts the same arguments as the where
method:
If you need to group an "or" condition within parentheses, you may pass a Closure as the first argument to the orWhere
method:
Additional Where Clauses
whereBetween / orWhereBetween
The whereBetween
method verifies that a column's value is between two values:
whereNotBetween / orWhereNotBetween
The whereNotBetween
method verifies that a column's value lies outside of two values:
whereIn / whereNotIn / orWhereIn / orWhereNotIn
The whereIn
method verifies that a given column's value is contained within the given array:
The whereNotIn
method verifies that the given column's value is not contained in the given array:
If you are adding a huge array of integer bindings to your query, the
whereIntegerInRaw
orwhereIntegerNotInRaw
methods may be used to greatly reduce your memory usage.
whereNull / whereNotNull / orWhereNull / orWhereNotNull
The whereNull
method verifies that the value of the given column is NULL
:
The whereNotNull
method verifies that the column's value is not NULL
:
whereDate / whereMonth / whereDay / whereYear / whereTime
The whereDate
method may be used to compare a column's value against a date:
The whereMonth
method may be used to compare a column's value against a specific month of a year:
The whereDay
method may be used to compare a column's value against a specific day of a month:
The whereYear
method may be used to compare a column's value against a specific year:
The whereTime
method may be used to compare a column's value against a specific time:
whereColumn / orWhereColumn
The whereColumn
method may be used to verify that two columns are equal:
You may also pass a comparison operator to the method:
The whereColumn
method can also be passed an array of multiple conditions. These conditions will be joined using the and
operator:
Parameter Grouping
Sometimes you may need to create more advanced where clauses such as "where exists" clauses or nested parameter groupings. The Laravel query builder can handle these as well. To get started, let's look at an example of grouping constraints within parenthesis:
As you can see, passing a Closure
into the where
method instructs the query builder to begin a constraint group. The Closure
will receive a query builder instance which you can use to set the constraints that should be contained within the parenthesis group. The example above will produce the following SQL:
You should always group
orWhere
calls in order to avoid unexpected behavior when global scopes are applied.
Where Exists Clauses
The whereExists
method allows you to write where exists
SQL clauses. The whereExists
method accepts a Closure
argument, which will receive a query builder instance allowing you to define the query that should be placed inside of the "exists" clause:
The query above will produce the following SQL:
Subquery Where Clauses
Sometimes you may need to construct a where clause that compares the results of a subquery to a given value. You may accomplish this by passing a Closure and a value to the where
method. For example, the following query will retrieve all users who have a recent "membership" of a given type;
JSON Where Clauses
Laravel also supports querying JSON column types on databases that provide support for JSON column types. Currently, this includes MySQL 5.7, PostgreSQL, SQL Server 2016, and SQLite 3.9.0 (with the JSON1 extension). To query a JSON column, use the ->
operator:
You may use whereJsonContains
to query JSON arrays (not supported on SQLite):
MySQL and PostgreSQL support whereJsonContains
with multiple values:
You may use whereJsonLength
to query JSON arrays by their length:
Ordering, Grouping, Limit & Offset
orderBy
The orderBy
method allows you to sort the result of the query by a given column. The first argument to the orderBy
method should be the column you wish to sort by, while the second argument controls the direction of the sort and may be either asc
or desc
:
latest / oldest
The latest
and oldest
methods allow you to easily order results by date. By default, result will be ordered by the created_at
column. Or, you may pass the column name that you wish to sort by:
inRandomOrder
The inRandomOrder
method may be used to sort the query results randomly. For example, you may use this method to fetch a random user:
reorder
The reorder
method allows you to remove all the existing orders and optionally apply a new order. For example, you can remove all the existing orders:
To remove all existing orders and apply a new order, provide the column and direction as arguments to the method:
groupBy / having
The groupBy
and having
methods may be used to group the query results. The having
method's signature is similar to that of the where
method:
You may pass multiple arguments to the groupBy
method to group by multiple columns:
For more advanced having
statements, see the havingRaw
method.
skip / take
To limit the number of results returned from the query, or to skip a given number of results in the query, you may use the skip
and take
methods:
Alternatively, you may use the limit
and offset
methods:
Conditional Clauses
Sometimes you may want clauses to apply to a query only when something else is true. For instance you may only want to apply a where
statement if a given input value is present on the incoming request. You may accomplish this using the when
method:
The when
method only executes the given Closure when the first parameter is true
. If the first parameter is false
, the Closure will not be executed.
You may pass another Closure as the third parameter to the when
method. This Closure will execute if the first parameter evaluates as false
. To illustrate how this feature may be used, we will use it to configure the default sorting of a query:
Inserts
The query builder also provides an insert
method for inserting records into the database table. The insert
method accepts an array of column names and values:
You may even insert several records into the table with a single call to insert
by passing an array of arrays. Each array represents a row to be inserted into the table:
The insertOrIgnore
method will ignore duplicate record errors while inserting records into the database:
Auto-Incrementing IDs
If the table has an auto-incrementing id, use the insertGetId
method to insert a record and then retrieve the ID:
When using PostgreSQL the
insertGetId
method expects the auto-incrementing column to be namedid
. If you would like to retrieve the ID from a different "sequence", you may pass the column name as the second parameter to theinsertGetId
method.
Updates
In addition to inserting records into the database, the query builder can also update existing records using the update
method. The update
method, like the insert
method, accepts an array of column and value pairs containing the columns to be updated. You may constrain the update
query using where
clauses:
Update Or Insert
Sometimes you may want to update an existing record in the database or create it if no matching record exists. In this scenario, the updateOrInsert
method may be used. The updateOrInsert
method accepts two arguments: an array of conditions by which to find the record, and an array of column and value pairs containing the columns to be updated.
The updateOrInsert
method will first attempt to locate a matching database record using the first argument's column and value pairs. If the record exists, it will be updated with the values in the second argument. If the record can not be found, a new record will be inserted with the merged attributes of both arguments:
Updating JSON Columns
When updating a JSON column, you should use ->
syntax to access the appropriate key in the JSON object. This operation is supported on MySQL 5.7+ and PostgreSQL 9.5+:
Increment & Decrement
The query builder also provides convenient methods for incrementing or decrementing the value of a given column. This is a shortcut, providing a more expressive and terse interface compared to manually writing the update
statement.
Both of these methods accept at least one argument: the column to modify. A second argument may optionally be passed to control the amount by which the column should be incremented or decremented:
You may also specify additional columns to update during the operation:
Model events are not fired when using the
increment
anddecrement
methods.
Deletes
The query builder may also be used to delete records from the table via the delete
method. You may constrain delete
statements by adding where
clauses before calling the delete
method:
If you wish to truncate the entire table, which will remove all rows and reset the auto-incrementing ID to zero, you may use the truncate
method:
Pessimistic Locking
The query builder also includes a few functions to help you do "pessimistic locking" on your select
statements. To run the statement with a "shared lock", you may use the sharedLock
method on a query. A shared lock prevents the selected rows from being modified until your transaction commits:
Alternatively, you may use the lockForUpdate
method. A "for update" lock prevents the rows from being modified or from being selected with another shared lock:
Debugging
You may use the dd
or dump
methods while building a query to dump the query bindings and SQL. The dd
method will display the debug information and then stop executing the request. The dump
method will display the debug information but allow the request to keep executing:
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