MySQL throws ER_TOO_MANY_FIELDS when a CREATE or ALTER TABLE statement defines more columns or total row size than the storage engine allows.
MySQL Error 1117: ER_TOO_MANY_FIELDS means your CREATE or ALTER TABLE exceeds MySQL’s column or row-size limits. Reduce column count, shorten data types, or split the table to fix the issue.
Too many columns
MySQL raises error 1117, ER_TOO_MANY_FIELDS - "Too many columns" - when a CREATE TABLE or ALTER TABLE statement defines more columns or total row size than the storage engine permits.
InnoDB allows up to 1017 columns and a maximum effective row size of about 65,535 bytes. MyISAM allows 4096 columns.
Surpassing either threshold stops table creation or modification.
Resolving the error is critical because DDL scripts halt, deployments fail, and applications depending on new schema changes cannot proceed.
Exceeding the hard cap of 1017 columns in InnoDB or 4096 in MyISAM directly triggers ER_TOO_MANY_FIELDS.
Combined row length beyond 65,535 bytes counts as "too many fields" even with fewer columns because MySQL sums maximum storage requirements during table definition.
Bulk migrations that loop over ALTER TABLE ...
ADD COLUMN can silently push schema past the limit and fail only on the final statement.
Changing storage engines reduces allowable columns, so moving a legacy MyISAM table to InnoDB may suddenly exceed limits.
Count existing columns with INFORMATION_SCHEMA.COLUMNS before running DDL.
Remove redundant columns, normalize wide tables, or group sparse attributes into JSON columns to reduce field count.
For oversized row length, move bulky TEXT or BLOB columns to a side table referenced by a foreign key.
After adjustments, re-run the CREATE or ALTER statement in a staging environment, then promote to production.
Audit-heavy schemas often add dozens of per-column timestamps.
Consolidate audit data into one JSON column.
CSV staging tables with hundreds of optional columns exceed limits. Load raw data into a staging file table, then pivot into normalized structures.
Product option matrices become unwieldy. Store rarely used attributes in an EAV or JSON model instead of dedicated columns.
Legacy MyISAM tables converted to InnoDB can break.
Review column counts and trim excess before migration.
Apply normalization principles early to keep tables narrow.
Monitor column counts with periodic queries against INFORMATION_SCHEMA and alert when approaching 800 columns in InnoDB.
Add lint rules in CI that parse DDL and fail builds if a table would exceed column or row-size limits.
Galaxy’s SQL editor surfaces these warnings inline, preventing errors before deployment.
Prefer JSON or child tables for optional or infrequently accessed attributes instead of ever-growing column lists.
ER_TOO_LONG_KEY – Index key length exceeds limit. Shorten indexed columns or use prefix indexes.
ER_TOO_MANY_KEYS – Table defines more than 64 secondary indexes. Drop or merge indexes.
ER_TOO_BIG_ROWSIZE – Row size exceeds 65,535 bytes in older MySQL versions. Reduce column sizes or split table.
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InnoDB supports a maximum of 1017 columns per table, but practical limits are lower because total row size must stay under 65,535 bytes.
The pointer to BLOB/TEXT columns counts toward the row length, so too many large fields can still trigger ER_TOO_MANY_FIELDS.
No. The limit is hard-coded in MySQL source. The only workaround is redesigning your schema.
Galaxy’s linting highlights column and row-size violations as you write DDL, allowing you to refactor before running the query against MySQL.
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