MySQL throws this error when the number of variables in a FETCH statement does not equal the number of columns returned by the cursor.
MySQL Error 1328: ER_SP_WRONG_NO_OF_FETCH_ARGS means the FETCH list has a different count than the cursor’s SELECT columns. Align the variable list with the SELECT column count or change the cursor query. Primary solution: make both counts identical before running the procedure.
Incorrect number of FETCH variables
MySQL raises error 1328 (SQLSTATE HY000) with the message "Incorrect number of FETCH variables" when a FETCH statement retrieves data from a cursor, but the list of local variables supplied differs from the number of columns produced by the cursor's SELECT.
The mismatch can be either too many or too few variables. Because MySQL cannot implicitly drop or create columns, it stops the stored routine at the FETCH call, leaving transactions or handlers in an uncertain state.
The most common trigger is defining a cursor with one column set and later changing the variable list or the underlying table schema without updating both sides.
Using SELECT * in the cursor definition is risky because future schema changes alter the column count, silently breaking the procedure until the next FETCH call.
First, compare the SELECT list inside the cursor declaration with the variables listed in the FETCH statement. Adjust whichever side is wrong so both counts match.
Recompile the stored procedure after changes. Always test with a small data set to confirm that the FETCH executes without errors.
If an ALTER TABLE added a column, explicitly list required columns in the cursor to keep a stable count.
When different branches of dynamic SQL return varying columns, standardize the SELECT list or prepare separate cursors for each path.
Always specify column names in the cursor’s SELECT instead of using SELECT *. This freezes the column count even if the table evolves.
Include routine tests in your CI pipeline. Galaxy’s version control surfacing schema diffs highlights when column counts change, alerting developers before deployment.
Error 1329 (ER_SP_BAD_FETCH_SEQ) occurs if FETCH is called before OPEN or after CLOSE. Error 1330 (ER_SP_BAD_RETURN_ARRAY) happens when returning result sets incorrectly. Each requires verifying cursor lifecycle or RETURN usage.
The SELECT inside the cursor returns a different number of columns than the FETCH variable list, leading to immediate failure.
Schema changes modify the SELECT * result, creating an unexpected column count at runtime.
Wildcard selection makes the cursor fragile because any schema change alters the column count without code changes.
Dynamic SQL that switches columns based on conditions can cause mismatches if the FETCH list is static.
Triggered when FETCH is executed before OPEN or after CLOSE. Verify cursor lifecycle.
Occurs when a stored routine returns an array improperly. Ensure correct RETURN syntax.
Appears when DECLARE specifies an incorrect parameter count. Align DECLARE parameters and procedure header.
No. The procedure halts on the FETCH line, and subsequent statements will not run. Fix the mismatch first.
Yes. Variables receive columns positionally. Even with the correct count, wrong order corrupts data.
Not immediately, but any future column change will break the procedure. Use explicit columns to stay safe.
Galaxy surfaces schema diffs and highlights stored routines that reference changed tables, letting you update cursor SELECT lists before deployment.
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