Tag Archives: mysql

PDO: Execute a prepared statement using array for IN clause

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See Example #5 here.

/* Execute a prepared statement using an array of values for an IN clause */
$params = array(1, 21, 63, 171);
/* Create a string for the parameter placeholders filled to the number of params */
$place_holders = implode(',', array_fill(0, count($params), '?'));

/*
    This prepares the statement with enough unnamed placeholders for every value
    in our $params array. The values of the $params array are then bound to the
    placeholders in the prepared statement when the statement is executed.
    This is not the same thing as using PDOStatement::bindParam() since this
    requires a reference to the variable. PDOStatement::execute() only binds
    by value instead.
*/
$sth = $dbh->prepare("SELECT id, name FROM contacts WHERE id IN ($place_holders)");
$sth->execute($params);

psql show tables

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I wanted to know what the analogue for MySQL ‘show tables’ was in PostgreSQL, and I found the answer, use the information_schema, here:

mysql: SHOW TABLES
postgresql: \d
postgresql: SELECT table_name FROM information_schema.tables WHERE table_schema = 'public';

mysql: SHOW DATABASES
postgresql: \l
postgresql: SELECT datname FROM pg_database;

mysql: SHOW COLUMNS
postgresql: \d table
postgresql: SELECT column_name FROM information_schema.columns WHERE table_name ='table';

mysql: DESCRIBE TABLE
postgresql: \d+ table
postgresql: SELECT column_name FROM information_schema.columns WHERE table_name ='table';

MySQL INET_ATON and INET_NTOA

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You can convert an IP address to an int, and vice versa, with these two MySQL functions. Of course I learned about this after I’d already implemented IP address support using BINARY(4) and my own parser/formatter… now that I have my own implementation I can’t bring myself to let it go, and I worry about support for signed/unsigned 32-bit ints (perhaps my concerns are unfounded..?)