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Translate date arithmetic written with INTERVAL operators #510

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112 changes: 101 additions & 11 deletions packages/mysql-on-sqlite/src/sqlite/class-wp-mysql-on-sqlite.php
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Original file line number Diff line number Diff line change
Expand Up @@ -4341,6 +4341,8 @@ private function translate( $node ): ?string {
return null;
}
return $this->translate_sequence( $node->get_children() );
case 'bitExpr':
return $this->translate_bit_expr( $node );
case 'simpleExprBody':
return $this->translate_simple_expr_body( $node );
case 'predicateOperations':
Expand Down Expand Up @@ -4907,9 +4909,70 @@ private function translate_simple_expr_body( WP_Parser_Node $node ): string {
}
}

// Translate "INTERVAL n unit + expr", the prefix form of date arithmetic.
if ( null !== $token && WP_MySQL_Lexer::INTERVAL_SYMBOL === $token->id ) {
$nodes = $node->get_child_nodes();
return $this->translate_interval_arithmetic(
$this->translate( $nodes[2] ),
false,
$nodes[0],
$nodes[1]
);
}

return $this->translate_sequence( $node->get_children() );
}

/**
* Translate a "bitExpr" AST node.
*
* Date arithmetic is the only "bitExpr" form that SQLite cannot run as
* written: "expr + INTERVAL n unit" and "expr - INTERVAL n unit". Each
* interval is folded into the expression on its left, so a chain such as
* "expr + INTERVAL 5 HOUR + INTERVAL 1 DAY" becomes nested DATETIME() calls
* applied in the same order as in MySQL.
*
* @param WP_Parser_Node $node The "bitExpr" AST node.
* @return string|null The translated value.
* @throws WP_MySQL_On_SQLite_Exception When the translation fails.
*/
private function translate_bit_expr( WP_Parser_Node $node ): ?string {
if ( ! $node->has_child_token( WP_MySQL_Lexer::INTERVAL_SYMBOL ) ) {
return $this->translate_sequence( $node->get_children() );
}

$children = $node->get_children();
$count = count( $children );
$parts = array();
for ( $i = 0; $i < $count; $i++ ) {
$child = $children[ $i ];
if (
$child instanceof WP_Parser_Token
&& ( WP_MySQL_Lexer::PLUS_OPERATOR === $child->id || WP_MySQL_Lexer::MINUS_OPERATOR === $child->id )
&& isset( $children[ $i + 1 ] )
&& $children[ $i + 1 ] instanceof WP_Parser_Token
&& WP_MySQL_Lexer::INTERVAL_SYMBOL === $children[ $i + 1 ]->id
) {
$parts = array(
$this->translate_interval_arithmetic(
implode( ' ', $parts ),
WP_MySQL_Lexer::MINUS_OPERATOR === $child->id,
$children[ $i + 2 ],
$children[ $i + 3 ]
),
);
$i += 3;
continue;
}

$translated = $this->translate( $child );
if ( null !== $translated ) {
$parts[] = $translated;
}
}
return implode( ' ', $parts );
}

/**
* Translate a MySQL CAST expression to SQLite.
*
Expand Down Expand Up @@ -5034,18 +5097,11 @@ private function translate_runtime_function_call( WP_Parser_Node $node ): string
case WP_MySQL_Lexer::DATE_ADD_SYMBOL:
case WP_MySQL_Lexer::DATE_SUB_SYMBOL:
$nodes = $node->get_child_nodes();
$value = $this->translate( $nodes[1] );
$unit = $this->translate( $nodes[2] );
if ( 'WEEK' === $unit ) {
$unit = 'DAY';
$value = 7 * $value;
}
return sprintf(
"DATETIME(%s, '%s' || %s || ' %s')",
return $this->translate_interval_arithmetic(
$this->translate( $nodes[0] ),
WP_MySQL_Lexer::DATE_SUB_SYMBOL === $child->id ? '-' : '+',
$value,
$unit
WP_MySQL_Lexer::DATE_SUB_SYMBOL === $child->id,
$nodes[1],
$nodes[2]
);
case WP_MySQL_Lexer::LEFT_SYMBOL:
$nodes = $node->get_child_nodes();
Expand All @@ -5059,6 +5115,40 @@ private function translate_runtime_function_call( WP_Parser_Node $node ): string
}
}

/**
* Translate MySQL date arithmetic to a SQLite DATETIME() call.
*
* SQLite reads the modifier as text, and "||" binds tighter than "*", so
* the value is parenthesized before the unit is appended. Subtraction
* negates the value instead of prefixing "-", which keeps a negative
* interval such as "INTERVAL -5 HOUR" valid: SQLite rejects "+-5 HOUR".
* A WEEK interval becomes seven days, as SQLite has no week modifier.
*
* @param string $expr The translated date expression.
* @param bool $subtract Whether the interval is subtracted.
* @param WP_Parser_Node $value The interval value expression node.
* @param WP_Parser_Node $interval The "interval" AST node holding the unit.
* @return string The translated value.
* @throws WP_MySQL_On_SQLite_Exception When the translation fails.
*/
private function translate_interval_arithmetic(
string $expr,
bool $subtract,
WP_Parser_Node $value,
WP_Parser_Node $interval
): string {
$value_sql = sprintf( '(%s)', $this->translate( $value ) );
$unit = strtoupper( $this->translate( $interval ) );
if ( 'WEEK' === $unit ) {
$value_sql = sprintf( '(%s * 7)', $value_sql );
$unit = 'DAY';
}
if ( $subtract ) {
$value_sql = '-' . $value_sql;
}
return sprintf( "DATETIME(%s, %s || ' %s')", $expr, $value_sql, $unit );
}

/**
* Translate a MySQL function call to SQLite.
*
Expand Down
116 changes: 115 additions & 1 deletion packages/mysql-on-sqlite/tests/WP_MySQL_On_SQLite_Tests.php
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -930,6 +930,120 @@ public function testDateSubFunction() {
$this->assertEquals( '2007-01-02 13:29:17', $result[0]->output );
}

public function testDateAddFunctionWithNegativeAndComputedIntervals() {
// Expected values were taken from MySQL 8.4.
$result = $this->assertQuery(
"SELECT DATE_ADD('2024-01-01 10:00:00', INTERVAL -5 HOUR) as output"
);
$this->assertEquals( '2024-01-01 05:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT DATE_SUB('2024-01-01 10:00:00', INTERVAL -5 HOUR) as output"
);
$this->assertEquals( '2024-01-01 15:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT DATE_SUB('2024-01-01 10:00:00', INTERVAL 2 * 3 HOUR) as output"
);
$this->assertEquals( '2024-01-01 04:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT DATE_ADD('2024-01-01 10:00:00', INTERVAL 1 week) as output"
);
$this->assertEquals( '2024-01-08 10:00:00', $result[0]->output );
}

public function testIntervalArithmetic() {
// Expected values were taken from MySQL 8.4.
$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' - INTERVAL 5 HOUR as output"
);
$this->assertEquals( '2024-01-01 05:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' + INTERVAL 5 HOUR as output"
);
$this->assertEquals( '2024-01-01 15:00:00', $result[0]->output );

// The interval can also come first.
$result = $this->assertQuery(
"SELECT INTERVAL 5 HOUR + '2024-01-01 10:00:00' as output"
);
$this->assertEquals( '2024-01-01 15:00:00', $result[0]->output );

// Intervals chain from left to right.
$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' + INTERVAL 5 HOUR + INTERVAL 1 DAY as output"
);
$this->assertEquals( '2024-01-02 15:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' + INTERVAL 1 DAY - INTERVAL 5 HOUR as output"
);
$this->assertEquals( '2024-01-02 05:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' + INTERVAL 1 WEEK as output"
);
$this->assertEquals( '2024-01-08 10:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' + INTERVAL 1 hour as output"
);
$this->assertEquals( '2024-01-01 11:00:00', $result[0]->output );

// The value is an expression, and may be negative or a string.
$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' - INTERVAL 2 * 3 HOUR as output"
);
$this->assertEquals( '2024-01-01 04:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' + INTERVAL -5 HOUR as output"
);
$this->assertEquals( '2024-01-01 05:00:00', $result[0]->output );

$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' + INTERVAL '5' HOUR as output"
);
$this->assertEquals( '2024-01-01 15:00:00', $result[0]->output );

// NULL on either side yields NULL.
$result = $this->assertQuery( 'SELECT NULL + INTERVAL 1 DAY as output' );
$this->assertNull( $result[0]->output );

$result = $this->assertQuery(
"SELECT '2024-01-01 10:00:00' + INTERVAL NULL DAY as output"
);
$this->assertNull( $result[0]->output );

// The case from the original report.
$result = $this->assertQuery(
"SELECT DATE('2024-01-01 10:00:00' - INTERVAL 5 HOUR) as output"
);
$this->assertEquals( '2024-01-01', $result[0]->output );
}

public function testIntervalArithmeticOnColumns() {
$this->assertQuery( 'CREATE TABLE _events (id INT, occurred_at DATETIME)' );
$this->assertQuery(
"INSERT INTO _events VALUES (1, '2024-01-01 10:00:00'), (2, '2024-01-03 10:00:00'), (3, NULL)"
);

// Expected values were taken from MySQL 8.4.
$result = $this->assertQuery(
'SELECT id, occurred_at - INTERVAL 1 DAY as output FROM _events ORDER BY id'
);
$this->assertEquals( '2023-12-31 10:00:00', $result[0]->output );
$this->assertEquals( '2024-01-02 10:00:00', $result[1]->output );
$this->assertNull( $result[2]->output );

$result = $this->assertQuery(
"SELECT id FROM _events WHERE occurred_at > '2024-01-02 00:00:00' - INTERVAL 1 DAY ORDER BY id"
);
$this->assertEquals( array( 1, 2 ), array_map( 'intval', array_column( $result, 'id' ) ) );
}

public function testLeftFunction1Char() {
$result = $this->assertQuery(
'SELECT LEFT("abc", 1) as output'
Expand Down Expand Up @@ -13133,7 +13247,7 @@ public function testCreateTableWithDefaultExpressions(): void {
$result = $this->sqlite->query( 'PRAGMA table_info(t)' )->fetchAll();
$this->assertSame( null, $result[0]['dflt_value'] );
$this->assertSame( '1 + 2', $result[1]['dflt_value'] );
$this->assertSame( "DATETIME(CURRENT_TIMESTAMP, '+' || 1 || ' YEAR')", $result[2]['dflt_value'] );
$this->assertSame( "DATETIME(CURRENT_TIMESTAMP, (1) || ' YEAR')", $result[2]['dflt_value'] );
$this->assertSame( "('a' || 'b')", $result[3]['dflt_value'] );
}

Expand Down
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