The purpose of the DESCRIBE command is to inspect the structure of a table — not its data. In other words, it tells you what columns exist and how they’re defined.
What DESCRIBE does in MySQL
DESCRIBE answers questions like:
- What columns does this table have?
- What are their data types?
- Which columns can be
NULL? - Which column is the primary key?
- Are there default values?
It’s a schema-inspection tool, not a data query.
Basic syntax
DESCRIBE table_name;
Example:
DESCRIBE users;
Typical output (what each column means)
| Column | Meaning |
|---|---|
Field | Column name |
Type | Data type (e.g., int, varchar(255)) |
Null | Whether NULL is allowed |
Key | Index type (PRI, UNI, MUL) |
Default | Default value |
Extra | Auto-increment, generated, etc. |
This tells you how the table is built.
Why DESCRIBE is important
1️⃣ Fast orientation
When you inherit a database (very common), DESCRIBE lets you understand a table in seconds.
2️⃣ Safer querying
Before writing:
SELECT something FROM table;
You check:
DESCRIBE table;
So you don’t guess column names or types.
3️⃣ Debugging & validation
- Why is an insert failing?
- Why can’t a column be NULL?
- Why is a value auto-incrementing?
DESCRIBE usually answers immediately.
DESCRIBE vs SELECT
This distinction is fundamental:
| Command | Purpose |
|---|---|
DESCRIBE table | Structure (schema) |
SELECT * FROM table | Data (rows) |
Think:
- DESCRIBE = blueprint
- SELECT = contents
Related commands you should know
SHOW COLUMNS FROM table;→ same result asDESCRIBESHOW CREATE TABLE table;→ full table definition (DDL)INFORMATION_SCHEMA→ advanced metadata queries
DESCRIBE is the quickest and most human-friendly option.
Best practice (training standard)
Always DESCRIBE a table before modifying or querying it.
This prevents:
- Typos
- Wrong assumptions
- Data loss
- Time wasted debugging
One-sentence definition (reusable)
DESCRIBEis used to view the structure and column definitions of a table in MySQL.
Related Topics:
- Compare
DESCRIBEvsSHOW CREATE TABLE - Apply this directly to WordPress or SuiteCRM tables
- Build a “first steps when exploring a database” checklist
- Show how GUI tools surface the same metadata
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