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joins.md

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Joins

Join clauses range from simple to complex including joining complete subqueries on multiple conditions. qb has your back with all of these use cases.

Table of Contents
join joinRaw joinSub joinWhere
leftJoin leftJoinRaw leftJoinSub newJoin
rightJoin rightJoinRaw rightJoinSub JoinClause
crossJoin crossJoinRaw crossJoinSub

join

Name Type Required Default Description
table string | Expression | JoinClause true ​ The name of the table or a Expression object from which the query is based. Alternatively, a configured JoinClause instance can be passed.
first string | Expression | Function false The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
type string false "inner" The type of the join. Passing this as an argument is discouraged for readability. Use the dedicated methods like leftJoin and rightJoin where possible.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use the dedicated joinWhere or a join closure where possible.

Applies a join to the query. The simplest join is to a table based on two columns:

{% code title="QueryBuilder" %}

query.from( "users" )
    .join( "posts", "users.id", "=", "posts.author_id" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`

{% endcode %}

When doing a simple join using = as the operator, you can omit it and pass just the column names:

{% code title="QueryBuilder" %}

query.from( "users" )
    .join( "posts", "users.id", "posts.author_id" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`

{% endcode %}

``Expressions are also supported as the table argument (though you may prefer the readability of the joinRaw method):

{% code title="QueryBuilder" %}

query.from( "users" )
    .join( query.raw( "posts (nolock)" ), "users.id", "=", "posts.author_id" );

{% endcode %}

{% code title="SQL Server" %}

SELECT *
FROM [users]
JOIN posts (nolock)
  ON [users].[id] = [posts].[author_id]

{% endcode %}

{% hint style="warning" %} Using raw will most likely tie your code to a specific database, so think carefully before using the raw method if you want your project to be database agnostic. {% endhint %}

When you need to specify more clauses to join, you can pass a function as the second argument:

{% code title="QueryBuilder" %}

query.from( "users" )
    .join( "posts", function( j ) {
        j.on( "users.id", "=", "posts.author_id" );
        j.on( "users.prefix", "=", "posts.prefix" );
    } );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`
  AND `users`.`prefix` = `posts`.`prefix`

{% endcode %}

You can specify where clauses in your joins as well.

{% code title="QueryBuilder" %}

query.from( "users" )
    .join( "posts", function( j ) {
        j.on( "users.id", "=", "posts.author_id" );
        j.whereNotNull( "posts.published_date" );
    } );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`
  AND `posts`.`published_date` IS NOT NULL

{% endcode %}

Conditions inside a join clause can be grouped using a function.

{% code title="QueryBuilder" %}

query.from( "users" )
    .join( "posts", function( j ) {
        j.on( function( j1 ) {
            j1.on( "users.id", "posts.author_id" )
                .orOn( "users.id", "posts.reviewer_id" );
        } );
        j.whereNotNull( "posts.published_date" );
    } );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON (
      `users`.`id` = `posts`.`author_id`
      OR `users`.`id` = `posts`.`reviewer_id`
  )
  AND `posts`.`published_date` IS NOT NULL

{% endcode %}

A preconfigured JoinClause can also be passed to the join function. This allows you to extract shared pieces of code out to different functions.

{% code title="QueryBuilder" %}

var j = query.newJoin( "contacts" )
    .on( "users.id", "posts.author_id" );

query.from( "users" ).join( j );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`

{% endcode %}

joinWhere

Name Type Required Default Description
table string true ​ The raw SQL string to use as the table.
first string | Expression | Function false The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
type string false "inner" The type of the join. Passing this as an argument is discouraged for readability. Use the dedicated methods like leftJoin and rightJoin with a join function where possible.

Adds a join to another table based on a WHERE clause instead of an ON clause. WHERE clauses introduce parameters and parameter bindings whereas on clauses join between columns and don't need parameter bindings.

For simple joins, this specifies a column on which to join the two tables:

{% code title="QueryBuilder" %}

query.from( "users" )
    .joinWhere( "contacts", "contacts.balance", "<", 100 );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `contacts`
  WHERE `contacts`.`balance` < ?

{% endcode %}

For complex joins, a function can be passed to first. This allows multiple on and where conditions to be applied to the join. See the documentation for join for more information.

joinRaw

Name Type Required Default Description
table string true ​ The raw SQL string to use as the table.
first string | Expression | Function false The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
type string false "inner" The type of the join. Passing this as an argument is discouraged for readability. Use the dedicated methods like leftJoinRaw and rightJoinRaw where possible.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use a closure to define the where clauses where possible.

Uses the raw SQL provided to as the table for the join clause. All the other functionality of joinRaw matches the join method. Additionally, there are leftJoinRaw, rightJoinRaw, and crossJoinRaw methods available.

{% code title="QueryBuilder" %}

query.from( "users" )
    .joinRaw( "posts (nolock)", "users.id", "posts.author_id" );

{% endcode %}

{% code title="SQL Server" %}

SELECT *
FROM [users]
JOIN posts (nolock)
  ON [users].[id] = [posts].[author_id]

{% endcode %}

{% hint style="warning" %} Using joinRaw will most likely tie your code to a specific database, so think carefully before using the joinRaw method if you want your project to be database agnostic. {% endhint %}

joinSub

Name Type Required Default Description
alias string true The alias for the derived table.
input Function | QueryBuilder true ​ Either a QueryBuilder instance or a function to define the derived query.
first string | Expression | Function true The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
type string false "inner" The type of the join. Passing this as an argument is discouraged for readability. Use the dedicated methods like leftJoinSub and rightJoinSub where possible.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use a closure to define the where clauses where possible.

Adds a join to a derived table. All the functionality of the join method applies to constrain the query. The derived table can be defined using a QueryBuilder instance:

{% code title="QueryBuilder" %}

var sub = query.newQuery()
    .select( "id" )
    .from( "contacts" )
    .whereNotIn( "id", [ 1, 2, 3 ] );

query.from( "users as u" )
    .joinSub( "c", sub, "u.id", "=", "c.id" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users` AS `u`
JOIN (
  SELECT `id`
  FROM `contacts`
  WHERE `id` NOT IN (?, ?, ?)
) AS `c`
  ON `u`.`id` = `c`.`id`

{% endcode %}

Alternatively, a function may be used to define the derived table:

{% code title="QueryBuilder" %}

query.from( "users as u" )
    .joinSub( "c", function ( q ) {
        q.select( "id" )
            .from( "contacts" )
            .whereNotIn( "id", [ 1, 2, 3 ] );
    }, "u.id", "=", "c.id" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users` AS `u`
JOIN (
  SELECT `id`
  FROM `contacts`
  WHERE `id` NOT IN (?, ?, ?)
) AS `c`
  ON `u`.`id` = `c`.`id`

{% endcode %}

Complex join conditions are also possible by passing a function as the third parameter:

{% code title="QueryBuilder" %}

query.from( "users as u" )
    .joinSub( "c", function ( q ) {
        q.select( "id" )
            .from( "contacts" )
            .whereNotIn( "id", [ 1, 2, 3 ] );
    }, function( j ) {
        j.on( "u.id", "c.id" );
        j.on( "u.type", "c.type" );
    } );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users` AS `u`
JOIN (
  SELECT `id`
  FROM `contacts`
  WHERE `id` NOT IN (?, ?, ?)
) AS `c`
  ON `u`.`id` = `c`.`id`
  AND `u`.`type` = `c`.`type`

{% endcode %}

leftJoin

Name Type Required Default Description
table string | Expression | JoinClause true ​

The name of the table or a Expression object from which the query is based. Alternatively, a configured JoinClause instance can be passed.

(Note: a JoinClause instance may have a different join type than a left join. The JoinClause instance's join type will be used.)
first string | Expression | Function false The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use a closure to define the where clauses where possible.

{% code title="QueryBuilder" %}

query.from( "posts" )
    .leftJoin( "users", "users.id", "posts.author_id" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `posts`
LEFT JOIN `users`
  ON `users`.`id` = `posts`.`author_id`

{% endcode %}

leftJoinRaw

Name Type Required Default Description
table string true ​ The raw SQL string to use as the table.
first string | Expression | Function false The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use a closure to define the where clauses where possible.

Uses the raw SQL provided to as the table for the left join clause. All the other functionality of leftJoinRaw matches the join method.

{% code title="QueryBuilder" %}

query.from( "posts" )
    .leftJoinRaw( "users (nolock)", "users.id", "posts.author_id" );

{% endcode %}

{% code title="SQL Server" %}

SELECT *
FROM [posts]
LEFT JOIN users (nolock)
  ON [users].[id] = [posts].[author_id]

{% endcode %}

{% hint style="warning" %} Using leftJoinRaw will most likely tie your code to a specific database, so think carefully before using the leftJoinRaw method if you want your project to be database agnostic. {% endhint %}

leftJoinSub

Name Type Required Default Description
alias string true The alias for the derived table.
input Function | QueryBuilder true ​ Either a QueryBuilder instance or a function to define the derived query.
first string | Expression | Function true The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use a closure to define the where clauses where possible.

Adds a left join to a derived table. All the functionality of the joinSub method applies to define and constrain the query.

{% code title="QueryBuilder" %}

var sub = query.newQuery()
    .select( "id" )
    .from( "contacts" )
    .whereNotIn( "id", [ 1, 2, 3 ] );

query.from( "users as u" )
    .leftJoinSub( "c", sub, "u.id", "=", "c.id" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users` AS `u`
LEFT JOIN (
  SELECT `id`
  FROM `contacts`
  WHERE `id` NOT IN (?, ?, ?)
) AS `c`
  ON `u`.`id` = `c`.`id`

{% endcode %}

rightJoin

Name Type Required Default Description
table string | Expression | JoinClause true ​

The name of the table or a Expression object from which the query is based. Alternatively, a configured JoinClause instance can be passed.

(Note: a JoinClause instance may have a different join type than a right join. The JoinClause instance's join type will be used.)
first string | Expression | Function false The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use a closure to define the where clauses where possible.

{% code title="QueryBuilder" %}

query.from( "users" )
    .rightJoin( "posts", "users.id", "posts.author_id" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
RIGHT JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`

{% endcode %}

rightJoinRaw

Name Type Required Default Description
table string true ​ The raw SQL string to use as the table.
first string | Expression | Function false The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use a closure to define the where clauses where possible.

Uses the raw SQL provided to as the table for the right join clause. All the other functionality of rightJoinRaw matches the join method.

{% code title="QueryBuilder" %}

query.from( "users" )
    .rightJoinRaw( "posts (nolock)", "users.id", "posts.author_id" );

{% endcode %}

{% code title="SQL Server" %}

SELECT *
FROM [users]
LEFT JOIN posts (nolock)
  ON [users].[id] = [posts].[author_id]

{% endcode %}

{% hint style="warning" %} Using rightJoinRaw will most likely tie your code to a specific database, so think carefully before using the rightJoinRaw method if you want your project to be database agnostic. {% endhint %}

rightJoinSub

Name Type Required Default Description
alias string true The alias for the derived table.
input Function | QueryBuilder true ​ Either a QueryBuilder instance or a function to define the derived query.
first string | Expression | Function true The first column or Expression to join the table on. Alternatively, a function can be passed to configure complex join statements.
operator string false "=" The boolean operator for the join clause.
second string | Expression false The second column or Expression to join the table on.
where boolean false false Sets if the value of second should be interpreted as a column or a value. Passing this as an argument is discouraged. Use a closure to define the where clauses where possible.

Adds a right join to a derived table. All the functionality of the joinSub method applies to define and constrain the query.

{% code title="QueryBuilder" %}

var sub = query.newQuery()
    .select( "id" )
    .from( "contacts" )
    .whereNotIn( "id", [ 1, 2, 3 ] );

query.from( "users as u" )
    .rightJoinSub( "c", sub, "u.id", "=", "c.id" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users` AS `u`
RIGHT JOIN (
  SELECT `id`
  FROM `contacts`
  WHERE `id` NOT IN (?, ?, ?)
) AS `c`
  ON `u`.`id` = `c`.`id`

{% endcode %}

crossJoin

Name Type Required Default Description
table string | Expression | JoinClause true ​

The name of the table or a Expression object from which the query is based. Alternatively, a configured JoinClause instance can be passed.

(Note: a JoinClause instance may have a different join type than a cross join. The JoinClause instance's join type will be used.)

{% code title="QueryBuilder" %}

query.from( "users" ).crossJoin( "posts" );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
CROSS JOIN `posts`

{% endcode %}

crossJoinRaw

Name Type Required Default Description
table string true ​ The raw SQL string to use as the table.

Uses the raw SQL provided to as the table for the cross join clause. Cross joins cannot be further constrained with on or where clauses.

{% code title="QueryBuilder" %}

query.from( "users" ).crossJoinRaw( "posts (nolock)" );

{% endcode %}

{% code title="SQL Server" %}

SELECT *
FROM [users]
CROSS JOIN posts (nolock)

{% endcode %}

{% hint style="warning" %} Using crossJoinRaw will most likely tie your code to a specific database, so think carefully before using the crossJoinRaw method if you want your project to be database agnostic. {% endhint %}

crossJoinSub

Name Type Required Default Description
alias string true The alias for the derived table.
input Function | QueryBuilder true ​ Either a QueryBuilder instance or a function to define the derived query.

Adds a cross join to a derived table. The derived table can be defined using a QueryBuilder instance or a function just as with joinSub. Cross joins cannot be constrained, however.

{% code title="QueryBuilder" %}

var sub = query.newQuery()
    .select( "id" )
    .from( "contacts" )
    .whereNotIn( "id", [ 1, 2, 3 ] );

query.from( "users as u" ).crossJoinSub( "c", sub );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users` AS `u`
CROSS JOIN (
  SELECT `id`
  FROM `contacts`
  WHERE `id` NOT IN (?, ?, ?)
)

{% endcode %}

crossApply

Name Type Required Default Description
name string true The name for the cross apply table
tableDef function | QueryBuilder true A QueryBuilder instance or a function that accepts a new query builder instance to configure.

Adds a cross apply join using a derived table. The derived table can be defined using a QueryBuilder instance or a function just as with joinSub.

{% code title="QueryBuilder" %}

qb.from( "users as u" )
    .select( [ "u.ID", "childCount.c" ] )
    .crossApply( "childCount", function( qb ) {
        qb.selectRaw( "count(*) c" )
            .from( "children" )
            .whereColumn( "children.parentID", "=", "users.ID" )
            .where( "children.someCol", "=", 0 );
    } )
    .where( "childCount.c", ">", 1 )

{% endcode %}

{% code title="SQL Server" %}

SELECT
    [u].[ID],
    [childCount].[c]
FROM [users] AS [u]
CROSS APPLY (
    SELECT count(*) c
    FROM [children]
    WHERE [children].[parentID] = [users].[ID]
    AND [children].[someCol] = ?
) AS [childCount]
WHERE [childCount].[c] > ?

{% endcode %}

outerApply

Name Type Required Default Description
name string true The name for the cross apply table
tableDef function | QueryBuilder true A QueryBuilder instance or a function that accepts a new query builder instance to configure.

Adds a outer apply join using a derived table. The derived table can be defined using a QueryBuilder instance or a function just as with joinSub.

{% code title="QueryBuilder" %}

qb.from( "users as u" )
    .select( [ "u.ID", "childCount.c" ] )
    .outerApply( "childCount", function( qb ) {
        qb.selectRaw( "count(*) c" )
            .from( "children" )
            .whereColumn( "children.parentID", "=", "users.ID" )
            .where( "children.someCol", "=", 0 );
    } )
    .where( "childCount.c", ">", 1 )

{% endcode %}

{% code title="SQL Server" %}

SELECT
    [u].[ID],
    [childCount].[c]
FROM [users] AS [u]
OUTER APPLY (
    SELECT count(*) c
    FROM [children]
    WHERE [children].[parentID] = [users].[ID]
    AND [children].[someCol] = ?
) AS [childCount]
WHERE [childCount].[c] > ?

{% endcode %}

newJoin

Name Type Required Default Description
table string | Expression true ​ The name of the table or a Expression object from which the query is based.
type string false "inner" The type of the join. Valid types are inner, left, right, or cross.

Creates a new JoinClause. A JoinClause is a specialized version of a QueryBuilder. You may call on or orOn to constrain the JoinClause. You may also call any where methods.

Creating a JoinClause directly is useful when you need to share a join between different queries. You can create and configure the JoinClause in a function and pass it to queries as needed.

{% code title="QueryBuilder" %}

var j = query.newJoin( "contacts" )
    .on( "users.id", "posts.author_id" );

query.from( "users" ).join( j );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`

{% endcode %}

{% hint style="warning" %} Although a JoinClause can be passed to join, leftJoin, rightJoin, and crossJoin, the type of the JoinClause will override the type of the function. {% endhint %}

{% code title="QueryBuilder" %}

// This is still an inner join because
// the JoinClause is an inner join
var j = query.newJoin( "contacts", "inner" )
    .on( "users.id", "posts.author_id" );

query.from( "users" ).leftJoin( j );

{% endcode %}

{% code title="MySQL" %}

-- This is still an inner join because
-- the JoinClause is an inner join
SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`

{% endcode %}

JoinClause

A JoinClause is a specialized version of a QueryBuilder. You may call on or orOn to constrain the JoinClause. You may also call any where methods.

on

Name Type Required Default Description
first string | Expression | Function false The first column or Expressionof the condition. Alternatively, a function can be passed to nest conditions with parenthesis.
operator string false "=" The boolean operator for the condition.
second string | Expression false The second column or Expression of the condition.
combinator string false "and" The boolean combinator for the clause (e.g. "and" or "or").

Applies a join condition to the JoinClause. An alias for whereColumn.

{% code title="QueryBuilder" %}

var j = query.newJoin( "contacts" )
    .on( "users.id", "posts.author_id" );

query.from( "users" ).join( j );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`

{% endcode %}

orOn

Name Type Required Default Description
first string | Expression | Function false The first column or Expressionof the condition. Alternatively, a function can be passed to nest conditions with parenthesis.
operator string false "=" The boolean operator for the condition.
second string | Expression false The second column or Expression of the condition.

Applies a join condition to the JoinClause using an or combinator. An alias for orWhereColumn.

{% code title="QueryBuilder" %}

var j = query.newJoin( "contacts" )
    .on( "users.id", "posts.author_id" )
    .orOn( "users.id", "posts.reviewer_id" );

query.from( "users" ).join( j );

{% endcode %}

{% code title="MySQL" %}

SELECT *
FROM `users`
JOIN `posts`
  ON `users`.`id` = `posts`.`author_id`
  OR `users`.`id` = `posts`.`reviewer_id`

{% endcode %}

Preventing Duplicate Joins

You can optionally configure qb to ignore duplicate joins. With this setting turned on each JoinClause is inspected and checked if it matches any existing JoinClause instances on the query. This is useful if you have a table shared between optional constraints and want to ensure it is only added once.

You can opt-in to this behavior by setting preventDuplicateJoins = true in your moduleSettings in config/ColdBox.cfc.

moduleSettings = {
    "qb": {
         "preventDuplicateJoins": true  
    }
};