Common SQL errors across databases, query mistakes, and constraint violations with practical fixes.
Query contains a grammar violation that the database parser cannot interpret.
Inserting or updating a row that would create a duplicate value in a UNIQUE or PRIMARY KEY column.
Inserting, updating, or deleting a row that would break a referential integrity rule.
Inserting or updating a row with NULL in a column that requires a non-null value.
Two or more transactions block each other, waiting for locks the other holds.
A division operation receives zero as the denominator in a query.
SELECT clause includes columns that are neither grouped nor wrapped in aggregate functions.
Attempting to insert a string or binary value that exceeds the defined maximum column length.