upper

Applies to VAST Cluster 5.5.

Functions › Text basics › Case. Returns a string with every lower-case letter converted to upper case, including accented and other non-ASCII letters. ucase is the same function.

Syntax

upper(s)
ucase(s)

Returns: VARCHAR.

Aliases: ucase.

Set up the examples

The examples connect with the ADBC driver, as in VAST Query Engine (ADBC), and work in a schema called docs_sql_fn_upper. Set QE_ENDPOINT, AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY and VASTDB_BUCKET (SQL reference), and run the blocks in order in one Python session. Below each block is the output you should see.

This block connects, defines the run() and plan() helpers, and creates a table of four orders. The SKUs and country codes were typed in mixed case. The last row has no values:

import os
import re

import adbc_driver_manager
import adbc_driver_manager.dbapi as dbapi
import adbc_driver_vastdb

BUCKET = os.environ["VASTDB_BUCKET"]
SCHEMA = f'"{BUCKET}/docs_sql_fn_upper"'

conn = dbapi.connect(
    driver=adbc_driver_vastdb.get_driver_path(),
    db_kwargs={
        "vast.db.endpoint": os.environ["QE_ENDPOINT"],
        "vast.db.access_key": os.environ["AWS_ACCESS_KEY_ID"],
        "vast.db.secret_key": os.environ["AWS_SECRET_ACCESS_KEY"],
    },
    autocommit=True,
)

def server_message(e):
    """The server's message in a driver error, without the request ID or the echoed statement."""
    text = re.sub(r"\[req=0x[0-9a-f]+\]: ", "", str(e))
    found = (re.search(r'message: "(.*?)", request_id', text, re.S)
             or re.search(r"description: (.*)\)", text, re.S))
    message = found.group(1) if found else text.strip().splitlines()[-1]
    message = re.sub(r"^Plan query: '.*?' failed with: ", "", message, flags=re.S)
    message = re.split(r"\\n|\n", message)[0].replace('\\"', '"')
    return message.replace(BUCKET, "<bucket>")

def run(sql):
    """Run one statement. Print the rows it returns, or the error."""
    try:
        with conn.cursor() as cur:
            cur.execute(sql)
            rows = cur.fetchall() if cur.description else []
    except (adbc_driver_manager.Error, OSError) as e:
        print(f"{type(e).__name__}: {server_message(e)}")
    else:
        print(rows)

def plan(sql):
    """Print the plan without its ~N Rows lines: the table's row count, which can still be 0 just after an insert."""
    with conn.cursor() as cur:
        cur.execute("EXPLAIN " + sql)
        steps = cur.fetchall()[0][1]
    print("\n".join(line for line in steps.splitlines() if "Rows" not in line))

TABLE = f"{SCHEMA}.orders"
run(f"CREATE SCHEMA IF NOT EXISTS {SCHEMA}")
run(f"CREATE TABLE IF NOT EXISTS {TABLE} (id BIGINT, sku VARCHAR, country VARCHAR, city VARCHAR)")
run(f"INSERT INTO {TABLE} VALUES "
    "(1, 'ab-100', 'gb', 'London'), "
    "(2, 'Cd-200', 'Fr', 'Paris'), "
    "(3, 'ef-300', 'FR', 'Straßburg'), "
    "(4, NULL, NULL, NULL)")

[]
[]
[(4,)]

What it does

upper maps each lower-case letter to its upper-case form, one character at a time, and leaves everything else (capitals, digits, punctuation, spaces, emoji, combining marks) unchanged. It covers Unicode letters, not only ASCII. In every case below, one character maps to one character, so the result has as many characters as the input:

upper takes no language argument, so the mapping is the same for all text.

NULLs and edge cases

The same cases, as the cluster returns them. They use the table and helpers from Set up the examples:

run("SELECT upper(NULL), upper(''), upper('straße'), length(upper('straße')), upper('fi'), upper('ı'), upper('dž')")
run("SELECT upper('é'), upper('e\u0301'), ucase('a')")
run("SELECT upper('\\xAA'::BLOB)")
run("SELECT upper(['a', 'b'])")
run("SELECT upper(123)")

[(None, '', 'STRAẞE', 6, 'fi', 'I', 'DŽ')]
[('É', 'É', 'A')]
InternalError: Binder Error: No function matches the given name and argument types 'upper(BLOB)'. You might need to add explicit type casts.
InternalError: Binder Error: No function matches the given name and argument types 'upper(VARCHAR[])'. You might need to add explicit type casts.
InternalError: Binder Error: No function matches the given name and argument types 'upper(INTEGER_LITERAL)'. You might need to add explicit type casts.

Examples

The SKUs, country codes and cities in upper case, with ucase on the city. ß in row 3 becomes ẞ:

run(f"SELECT id, upper(sku), upper(country), ucase(city) FROM {TABLE} ORDER BY id LIMIT 10")

[(1, 'AB-100', 'GB', 'LONDON'), (2, 'CD-200', 'FR', 'PARIS'), (3, 'EF-300', 'FR', 'STRAẞBURG'), (4, None, None, None)]

Select the orders for France, however the country code was typed:

run(f"SELECT id, sku FROM {TABLE} WHERE upper(country) = 'FR' ORDER BY id LIMIT 10")

[(2, 'Cd-200'), (3, 'ef-300')]

How it runs in VAST

The Query Engine runs on the cluster's CNodes, and a query on a table starts with a scan in VAST DataBase (VAST_SCAN). VAST DataBase can evaluate a comparison of a column with a constant, but not a function of a column, so upper() of a column is always computed by the Query Engine:

• In the SELECT list, the scan reads the column and the Query Engine computes upper() for each row it returns.
• In WHERE, the scan sends the column for every row, and a FILTER step in the Query Engine computes upper() and keeps the rows that match. No rows are skipped in storage.

The plan of the France example shows the FILTER step above the scan:

plan(f"SELECT id FROM {TABLE} WHERE upper(country) = 'FR'")

┌───────────────────────────┐
│         PROJECTION        │
│    ────────────────────   │
│             #1            │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│           FILTER          │
│    ────────────────────   │
│  (upper(country) = 'FR')  │
│                           │
└─────────────┬─────────────┘
┌─────────────┴─────────────┐
│         VAST_SCAN         │
│    ────────────────────   │
│    Function: VAST_SCAN    │
│                           │
│        Projections:       │
│          country          │
│             id            │
│                           │
└───────────────────────────┘

Make it faster

• Normalize the case when you write the rows. If you always compare codes in upper case, store them in upper case, and apply upper() to the value you search for instead of the column. country = upper('fr') compares the raw column with a constant, which is pushed down to VAST DataBase, so rows that don't match never leave storage. In this table only row 3 was stored as FR, so it's the only match; the plan has no FILTER step:

run(f"SELECT id, sku FROM {TABLE} WHERE country = upper('fr') ORDER BY id LIMIT 10")
plan(f"SELECT id FROM {TABLE} WHERE country = upper('fr')")

[(3, 'ef-300')]
┌───────────────────────────┐
│         VAST_SCAN         │
│    ────────────────────   │
│    Function: VAST_SCAN    │
│      Projections: id      │
│                           │
└───────────────────────────┘

• Combine it with a pushed-down condition. In id > 1 AND upper(country) = 'FR', id > 1 is still evaluated in VAST DataBase, so upper() runs only on the rows that pass it.
• COLLATE nocase doesn't avoid the function. It's planned as a lower() filter; see COLLATE nocase and noaccent.

Limitations and errors

• Strings only. A number, a date, a boolean, a list or a BLOB fails with No function matches the given name and argument types; the error lists upper(VARCHAR) as the only form.
• One character for one character. ß becomes ẞ, and ligatures such as fi stay as they are. If a downstream system expects SS or FI, replace those characters in your code or with replace.
• No title case. initcap isn't available: it fails with Scalar Function with name initcap does not exist!. Capitalize words in your code.

run("SELECT initcap('ada lovelace')")

InternalError: Catalog Error: Scalar Function with name initcap does not exist!

Similar functions

run("SELECT upper('Straße'), ucase('Straße'), lower('Straße'), 'Straße' COLLATE nocase = 'STRAẞE'")

[('STRAẞE', 'STRAẞE', 'straße', True)]

Clean up:

run(f"DROP TABLE IF EXISTS {TABLE}")
run(f"DROP SCHEMA IF EXISTS {SCHEMA}")
conn.close()

[]
[]

See also

• Text basics: all the text functions.
• lower and COLLATE nocase and noaccent.
• Where filters run and pushdowns.
• EXPLAIN: how to read a plan.