CODEWITHSUNDEEP
mysqlprepared-statement
Mahdi_Nine
Mahdi_Nine

Reputation: 14751

problem with prepare statement

I write this query and it has error what is problem?

prepare test from
'select * from ?';

what is problem?

what is it's correct form?

Upvotes: 2

Views: 230

Answers (2)

ypercubeᵀᴹ
ypercubeᵀᴹ

Reputation: 115520

You can't just put a placeholder wherever you like. Parameter placeholders can appear only in those places inside the statement where you would normally expect an expression. In particular, you cannot use parameter placeholders to parameterize identifiers or entire statement structures. That's why your attempt fails.

Many more useful things regarding prepared statements and Dynamic SQL in MYSQL can be found in Roland Bouman's blog -> MySQL 5: Prepared statement syntax and Dynamic SQL.

If your intended use is something like:

prepare test
  from
    'select * from ?' ;
set @myt := 'myTable' ;
execute test
  using @myt ;

it will simply not work. But you can bypass it with:

set @myt := 'myTable'
set @qtext := concat('select * from ',@myt) ;
prepare test 
  from @qtext ;
execute test ;

Upvotes: 4

Erik B
Erik B

Reputation: 42554

I've never tried having the table name as a variable. I'm not sure that's allowed. Try the following:

PREPARE test FROM "SELECT * FROM table_name WHERE column = ?";

This is kind of a stab in the dark, since you're not providing the error message.

Upvotes: 1

Related Questions