How to get the size of a varchar

sql

database-schema-management

varchar-field-size

information-schema

byAlex Kataev·Nov 16, 2024

Effortlessly snag the defined size of a VARCHAR(n) field using:

SELECT CHARACTER_MAXIMUM_LENGTH 
FROM INFORMATION_SCHEMA.COLUMNS 
WHERE TABLE_NAME = 'my_table' AND COLUMN_NAME = 'my_column';

Replace 'my_table' and 'my_column' with your actual table and column names (unless you actually named your table "my_table", then carry on). This statement retrieves the VARCHAR length (n value), and it’s compatible with PostgreSQL, MySQL, SQL Server and other compliant databases.

Additionally, Stalwart SQL Server users can wield the COLUMNPROPERTY or the COL_LENGTH function for an insider approach.

Other dynamic methods: Adapt as you evolve

Evolution is key: some queries are dynamic, adapting to field size changes. No need to adjust your queries every time the column size does, and no manual labor needed here.

COLUMNPROPERTY gives plenty of metadata, including varchar width.
COL_LENGTH provides you column length for the specific table/column pair.
DATALENGTH(field) seizes how much data a field holds (surprise, surprise) in SQL Server.

Now, if you fancy a field trip, change the column size and re-run these queries.

Handling larger fields: Size matters not

Yoda once said, "Size matters not." Jedi wisdom applies here too. These beauties of methods can handle VARCHAR fields even with sizes being a Thor's hammer (way over 1000). Google it, trust me. Essential, especially when textual data can grow as long as Rapunzel's hair.

Efficiency with a side of adaptability

Nothing oozes efficiency like knowing your VARCHAR sizes. Whether it's detective work (read troubleshooting) or just your run-of-the-mill maintenance, field size measurement often saves the day in database schema management.

Now for the boring part, these solutions work on SQL Server 2008 and newer, not forgetting the numerous RDBMS that play nice due to INFORMATION_SCHEMA.

Consensus: The voice of the community

Great empires were built with consensus, and the same holds true in the world of code. From INFORMATION_SCHEMA.COLUMNS, COLUMNPROPERTY, to COL_LENGTH, the battle-tested palette of solutions that developers rely on for their daily grind.

Database agnosticism: Versatility at its finest

Need to cater to multiple databases? The INFORMATION_SCHEMA.COLUMNS query has your back. It's a solid pick across different databases, making the database agonistic quest a child's play.

FLAVORful Preferences

Guess what? DB's have flavors, just like Baskin Robbins! The community's love for INFORMATION_SCHEMA stems from its cross-database compatibility. Who wouldn't like a tool that eases relocation across diverse environments?

Simplicity with a dash of effectiveness

Here's a secret recipe: take a pinch of simplicity, a dash of effectiveness, and voila! You have tools ranking top by votes! Our beloved INFORMATION_SCHEMA fits the bill, making it an effortless choice for hungry developers. Digestible for beginners, and a breeze for the experts alike.

The grand scheme

Beneath layers of queries and data rows, efficient database schema management is the Superman keeping your data safe and sound. VARCHAR field size knowledge sweetens the deal, paving the way for lean and mean database architectures.

explain-codes / Sql / How to get the size of a varchar[n] field in one SQL statement?

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