How do you check if SQL query is empty in PHP?

How do I check if a query is empty in PHP?

The empty() function checks whether a variable is empty or not. This function returns false if the variable exists and is not empty, otherwise it returns true. The following values evaluates to empty: 0.

How do I check if a SQL query is empty?

The IS NULL condition is used in SQL to test for a NULL value. It returns TRUE if a NULL value is found, otherwise it returns FALSE. It can be used in a SELECT, INSERT, UPDATE, or DELETE statement.

How do I check if SQL query returns nothing in PHP?

mysql_query() will only return FALSE if the query failed. It will return TRUE even if you have no rows, but successfully queried the database. This should work. If a query returns nothing it will be a boolean result and it’s value will be 0.

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How do you check if SQL query is correct in PHP?

“check if a sql query has been executed php” Code Answer

  1. <? php.
  2. // peform a query.
  3. $query = “SELECT `*` FROM user”;
  4. $results = mysqli_query($databaseConnection, $query);
  5. if (mysqli_num_rows($results) == 0) {
  6. // The query returned 0 rows!
  7. } else {

How do I know if mysql query has nothing returned?

mysql> SELECT * FROM ColumnValueNullDemo WHERE ColumnName IS NULL OR ColumnName = ‘ ‘; After executing the above query, the output obtained is. This output was obtained as the second condition is true for empty value.

How check variable is NULL in PHP?

The is_null() function checks whether a variable is NULL or not. This function returns true (1) if the variable is NULL, otherwise it returns false/nothing.

How do I view an empty table in SQL?

Get List of Empty Tables in SQL Server

  1. select.
  2. t. name table_name,
  3. s. name schema_name,
  4. sum(p. rows) total_rows.
  5. from.
  6. sys.tables t.
  7. join sys.schemas s on (t.schema_id = s.schema_id)
  8. join sys.partitions p on (t.object_id = p.object_id)

How do you check if a result set is empty?

The JDBC ResultSet doesn’t provide any isEmpty(), length() or size() method to check if its empty or not. Hence, when a Java programmer needs to determine if ResultSet is empty or not, it just calls the next() method and if next() returns false it means ResultSet is empty.

Is NULL or empty in SQL?

NULL is used in SQL to indicate that a value doesn’t exist in the database. It’s not to be confused with an empty string or a zero value. While NULL indicates the absence of a value, the empty string and zero both represent actual values.

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How can I tell if SQL insert was successful in PHP?

To check if your INSERT was successful, you can use mysqli_affected_rows() . Returns the number of rows affected by the last INSERT, UPDATE, REPLACE or DELETE query. Your present code is open to SQL injection if user interaction is involved. Use mysqli with prepared statements, or PDO with prepared statements.

How do I echo a query in PHP?

“how to echo query in php” Code Answer

  1. $sql = “SELECT id, firstname, lastname FROM MyGuests”;
  2. $result = $conn->query($sql);
  3. if ($result->num_rows > 0) {
  4. // output data of each row.
  5. while($row = $result->fetch_assoc()) {
  6. echo “id: ” . $ row[“id”]. ” – Name: ” . $ row[“firstname”]. ” ” . $ row[“lastname”]. “< …
  7. }
  8. } else {

How do I check if a SQL query is correct?

To verify a query i use the EXPLAIN command. You can take any SQL query and add EXPLAIN before it and execute. If query is wrong, error will be returned.

How check MySQL update query was successful in PHP?

4 Answers. Use if(mysqli_affected_rows($mysqli) >0 ) or no comparison at all. Sidenote: ==1 is only comparing for 1, as opposed to >0 which you may be trying to update more than one row.

Which is the correct function to execute the SQL queries in PHP?

PHP mysqli_query function

The mysqli_query function is used to execute SQL queries.

How do you query a MySQL table with help of PHP?

Its basic syntax is as follows: SELECT column1_name, column2_name, columnN_name FROM table_name; Let’s make a SQL query using the SELECT statement, after that we will execute this SQL query through passing it to the PHP mysqli_query() function to retrieve the table data.

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