<p>The error appears when a stored procedure or function receives an OUT or INOUT argument that is not a writable variable.</p>
<p>MySQL Error 1414 ER_SP_NOT_VAR_ARG occurs when an OUT or INOUT parameter is supplied with a literal, expression, or NEW pseudo-variable instead of a writable variable. Pass a user or local variable (e.g., @out_val) or move the call to an AFTER trigger to fix the issue.</p>
OUT or INOUT argument %d for routine %s is not a variable
MySQL returns error 1414 when a stored procedure or function expects an OUT or INOUT parameter but the caller supplies something that cannot be written to, such as a literal, expression, constant, or the NEW pseudo-variable inside a BEFORE trigger.
The engine needs a true variable so it can write the outgoing value. If the argument is not writable the server aborts the statement and issues SQLSTATE 42000.
The error fires most often when developers pass numeric or string literals to an OUT parameter, call the routine inside a BEFORE trigger, or forward the argument from a view, subquery, or expression that resolves to a temporary column.
Another cause is using session variables incorrectly, for example omitting the @ prefix or trying to reuse the same literal in multiple places.
Always supply a variable that the server can modify. Create a user variable (@var_name), declare a local variable with DECLARE inside another routine, or use a prepared host variable in your client code.
In triggers choose an AFTER trigger instead of BEFORE when you need to capture output from a routine call, because BEFORE triggers cannot assign to NEW.
If you called a procedure like CALL get_totals(1,2); rewrite it as SET @out:=0; CALL get_totals(1,@out); SELECT @out;
In a BEFORE UPDATE trigger move the logic to an AFTER UPDATE trigger or store the output in a declared variable inside the trigger, then copy it to NEW columns if needed in an AFTER context.
Define clear parameter modes in routine headers and document expected caller syntax. Use named variables when testing procedures and include unit tests that check OUT assignments.
Enforce code reviews in Galaxy collections so peers can catch literal OUT parameters before they reach production.
Error 1193 Unknown system variable arises when you miss the @ prefix on user variables. Error 1366 Incorrect integer value appears when type casting fails inside routine parameters. The fixes are similar: supply correct variable references and data types.
Supplying 0 or 'text' instead of @out_var is the top trigger because literals are read-only.
Passing NOW() or CONCAT(...) to an OUT parameter creates a temporary, unwritable result.
NEW.column is read-only before the row exists; writing to it causes error 1414.
Raised when a user variable is referenced without the @ prefix.
Occurs when a DECLARE variable is used outside its scope.
Appears in triggers when OLD or NEW are referenced incorrectly.
No. Columns are read-only in CALL statements. Copy the value to a user variable first.
BEFORE triggers cannot assign to NEW because the row is not yet created. Use AFTER triggers instead.
Store the procedure output in a local variable inside the trigger and use it later rather than assigning directly to NEW.
Yes. Galaxy highlights literal OUT parameters in real time and suggests declaring a variable, reducing runtime failures.
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