# 查询语言.aggregate

数据库聚合查询功能。

Uses

<?php

use Leevel\Database\Condition;
use Tests\Database\DatabaseTestCase as TestCase;

# 记录数量 count

计算记录数量。

函数原型

public function findCount(string $field = '*', string $alias = 'row_count', bool $flag = false);

TIP

可使用 findCount() 或者 count()->find() 来统计记录行。

public function testBaseUse(): void
{
    $connect = $this->createDatabaseConnectMock();

    $sql = <<<'eot'
        [
            "SELECT COUNT(*) AS row_count FROM `test_query` LIMIT 1",
            [],
            false
        ]
        eot;

    $this->assertSame(
        $sql,
        $this->varJson(
            $connect
                ->table('test_query')
                ->count()
                ->findOne(true)
        )
    );

    $sql = <<<'eot'
        [
            "SELECT COUNT(`test_query`.`id`) AS row_count FROM `test_query` LIMIT 1",
            [],
            false
        ]
        eot;

    $this->assertSame(
        $sql,
        $this->varJson(
            $connect
                ->table('test_query')
                ->count('id')
                ->findOne(true),
            1
        )
    );

    $sql = <<<'eot'
        [
            "SELECT COUNT(`test_query`.`id`) AS count1 FROM `test_query` LIMIT 1",
            [],
            false
        ]
        eot;

    $this->assertSame(
        $sql,
        $this->varJson(
            $connect
                ->table('test_query')
                ->count('id', 'count1')
                ->findOne(true),
            2
        )
    );

    $sql = <<<'eot'
        [
            "SELECT COUNT(`test_query`.`id`*50) AS count1 FROM `test_query` LIMIT 1",
            [],
            false
        ]
        eot;

    $this->assertSame(
        $sql,
        $this->varJson(
            $connect
                ->table('test_query')
                ->count(Condition::raw('[id]*50'), 'count1')
                ->findOne(true),
            3
        )
    );
}

# 平均值 avg

计算平均值。

public function testAvg(): void
{
    $connect = $this->createDatabaseConnectMock();

    $sql = <<<'eot'
        [
            "SELECT AVG(`test_query`.`id`) AS avg_value FROM `test_query` LIMIT 1",
            [],
            false
        ]
        eot;

    $this->assertSame(
        $sql,
        $this->varJson(
            $connect
                ->table('test_query')
                ->avg('id')
                ->findOne(true)
        )
    );
}

# 最大值 max

计算最大值。

public function testMax(): void
{
    $connect = $this->createDatabaseConnectMock();

    $sql = <<<'eot'
        [
            "SELECT MAX(`test_query`.`num`) AS max_value FROM `test_query` LIMIT 1",
            [],
            false
        ]
        eot;

    $this->assertSame(
        $sql,
        $this->varJson(
            $connect
                ->table('test_query')
                ->max('num')
                ->findOne(true)
        )
    );
}

# 最小值 min

计算最小值。

public function testMin(): void
{
    $connect = $this->createDatabaseConnectMock();

    $sql = <<<'eot'
        [
            "SELECT MIN(`test_query`.`num`) AS min_value FROM `test_query` LIMIT 1",
            [],
            false
        ]
        eot;

    $this->assertSame(
        $sql,
        $this->varJson(
            $connect
                ->table('test_query')
                ->min('num')
                ->findOne(true)
        )
    );
}

# 合计 sum

计算合计。

public function testSum(): void
{
    $connect = $this->createDatabaseConnectMock();

    $sql = <<<'eot'
        [
            "SELECT SUM(`test_query`.`num`) AS sum_value FROM `test_query` LIMIT 1",
            [],
            false
        ]
        eot;

    $this->assertSame(
        $sql,
        $this->varJson(
            $connect
                ->table('test_query')
                ->sum('num')
                ->findOne(true)
        )
    );
}