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don't split on ',' if within a function

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This commit is contained in:
Matthew Bucci
2023-10-30 14:24:27 -07:00
parent ee6328fca7
commit ec9079d9c9
7 changed files with 100 additions and 24 deletions
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pg4wp/rewriters/SelectSQLRewriter.php
+45 -19
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@@ -16,11 +16,11 @@ class SelectSQLRewriter extends AbstractSQLRewriter
error_log('[' . microtime(true) . "] Number of rows required for :\n$sql\n---------------------\n", 3, PG4WP_LOG . 'pg4wp_NUMROWS.log');
}
}
if(false !== strpos($sql, 'FOUND_ROWS()')) {
// Here we convert the latest query into a COUNT query
$sql = $GLOBALS['pg4wp_numrows_query'];
// Remove the LIMIT clause if it exists
$sql = preg_replace('/\s+LIMIT\s+\d+(\s*,\s*\d+)?/i', '', $sql);
@@ -232,6 +232,26 @@ class SelectSQLRewriter extends AbstractSQLRewriter
return $postgresSql;
}
/**
* Transforms a given SQL query to include a GROUP BY clause if the SELECT statement has both aggregate
* and non-aggregate columns. This function is specifically designed to work with PostgreSQL.
*
* In PostgreSQL, a query that uses aggregate functions must group by all columns in the SELECT list that
* are not part of the aggregate functions. Failing to do so results in a syntax error. This function
* automatically adds a GROUP BY clause to meet this PostgreSQL requirement when both aggregate (COUNT, SUM,
* AVG, MIN, MAX) and non-aggregate columns are present.
*
* @param string $sql The SQL query string to be transformed.
*
* @return string The transformed SQL query string with appropriate GROUP BY clause if required.
*
* @throws Exception If the SQL query cannot be parsed or modified.
*
* @example
* Input: SELECT COUNT(id), username FROM users;
* Output: SELECT COUNT(id), username FROM users GROUP BY username;
*
*/
protected function ensureGroupByOrAggregate(string $sql): string
{
// Check for system or session variables
@@ -239,7 +259,7 @@ class SelectSQLRewriter extends AbstractSQLRewriter
return $sql;
}
// Regular expression to capture main SQL components
// Regular expression to capture main SQL components.
$regex = '/(SELECT\s+)(.*?)(\s+FROM\s+)([^ ]+)(\s+WHERE\s+.*?(?= ORDER BY | GROUP BY | LIMIT |$))?(ORDER BY.*?(?= LIMIT |$))?(LIMIT.*?$)?/is';
// Capture main SQL components using regex
@@ -247,22 +267,26 @@ class SelectSQLRewriter extends AbstractSQLRewriter
return $sql;
}
$selectClause = $matches[2] ?? '';
$fromClause = $matches[4] ?? '';
$whereClause = $matches[5] ?? '';
$orderClause = $matches[6] ?? '';
$limitClause = $matches[7] ?? '';
$selectClause = trim($matches[2]) ?? '';
$fromClause = trim($matches[4]) ?? '';
$whereClause = trim($matches[5]) ?? '';
$orderClause = trim($matches[6]) ?? '';
$limitClause = trim($matches[7]) ?? '';
if (empty($selectClause) || empty($fromClause)) {
return $sql;
}
$columns = explode(',', $selectClause);
// Regular expression to match commas not within parentheses
$pattern = '/,(?![^\(]*\))/';
// Split columns using a comma, and then trim each element
$columns = array_map('trim', preg_split($pattern, $selectClause));
$aggregateColumns = [];
$nonAggregateColumns = [];
foreach ($columns as $col) {
$col = trim($col);
// Check for aggregate functions in the column
if (preg_match('/(COUNT|SUM|AVG|MIN|MAX)\s*?\(/i', $col)) {
$aggregateColumns[] = $col;
} else {
@@ -275,23 +299,25 @@ class SelectSQLRewriter extends AbstractSQLRewriter
return $sql;
}
$groupByClause = "GROUP BY " . implode(", ", $nonAggregateColumns);
// Assemble new SQL query
$postgresSql = "SELECT $selectClause FROM $fromClause";
if (!empty(trim($whereClause))) {
$postgresSql .= " $whereClause";
if (!empty($whereClause)) {
$postgresSql .= ' ' . $whereClause;
}
$postgresSql .= " $groupByClause";
if (!empty(trim($orderClause))) {
$postgresSql .= " $orderClause";
$groupByClause = "GROUP BY " . implode(", ", $nonAggregateColumns);
if (!empty($groupByClause)) {
$postgresSql .= ' ' . $groupByClause;
}
if (!empty(trim($limitClause))) {
$postgresSql .= " $limitClause";
if (!empty($orderClause)) {
$postgresSql .= ' ' . $orderClause;
}
if (!empty($limitClause)) {
$postgresSql .= ' ' . $limitClause;
}
return $postgresSql;