CAST(expression AS target_type)
-- Or using :: operator (Snowflake, Databricks)
expression::

TRY_CAST(expression AS target_type)
-- Returns NULL instead of error on failure

-- Snowflake
TO_NUMBER(expression)
TO_VARCHAR(expression)
TO_DATE(expression)
TO_TIMESTAMP(expression)

-- BigQuery
CAST(expression AS type)
SAFE_CAST(expression AS type)  -- Like TRY_CAST

SELECT 
    -- String to number
    CAST('123' AS INTEGER) as str_to_int,
    CAST('123.45' AS DECIMAL(10,2)) as str_to_decimal,
    
    -- Number to string
    CAST(123 AS VARCHAR) as int_to_str,
    CAST(123.45 AS VARCHAR) as decimal_to_str,
    
    -- String to date
    CAST('2024-01-15' AS DATE) as str_to_date,
    
    -- Date to string
    CAST(CURRENT_DATE AS VARCHAR) as date_to_str,
    
    -- Timestamp conversions
    CAST('2024-01-15 10:30:00' AS TIMESTAMP) as

SELECT 
    value,
    CAST(value AS INTEGER) as cast_result,      -- Fails on 'invalid'
    TRY_CAST(value AS INTEGER) as try_cast_result  -- Returns NULL
FROM (
    VALUES ('123'), ('456'), ('invalid'), (NULL)
) AS t(value)

SELECT 
    value,
    CAST(value AS INT64) as cast_result,
    SAFE_CAST(value AS INT64) as safe_cast_result
FROM UNNEST(['123', '456', 'invalid', NULL]) AS value

SELECT 
    customer_id,
    phone_raw,
    email_raw,
    age_raw,
    -- Clean and convert
    TRY_CAST(phone_raw AS VARCHAR(20)) as phone_clean,
    TRY_CAST(age_raw AS INTEGER) as age_clean,
    -- Flag invalid data
    CASE 
        WHEN TRY_CAST(age_raw AS INTEGER) IS NULL AND age_raw IS NOT NULL 
        THEN 'Invalid Age'
        ELSE 'Valid'
    END as data_quality_flag
FROM customer_import
WHERE TRY_CAST(age_raw AS INTEGER) IS NOT NULL OR age_raw IS NULL

SELECT 
    -- String to date with format
    TO_DATE('01/15/2024', 'MM/DD/YYYY') as us_date,
    TO_DATE('15/01/2024', 'DD/MM/YYYY') as eu_date,
    
    -- String to timestamp
    TO_TIMESTAMP('2024-01-15 14:30:00', 'YYYY-MM-DD HH24:MI:SS') as timestamp_val,
    
    -- Unix timestamp to timestamp
    TO_TIMESTAMP(1705329000) as from_unix,
    
    -- Extract parts
    TO_NUMBER(TO_CHAR(CURRENT_DATE, 'YYYY')) as

SELECT 
    -- Parse date with format
    PARSE_DATE('%m/%d/%Y', '01/15/2024') as us_date,
    PARSE_DATE('%d/%m/%Y', '15/01/2024') as eu_date,
    
    -- Parse timestamp
    PARSE_TIMESTAMP('%Y-%m-%d %H:%M:%S', '2024-01-15 14:30:00') as timestamp_val,
    
    -- Unix timestamp
    TIMESTAMP_SECONDS(1705329000) as from_unix,
    
    -- Format date
    FORMAT_DATE('%Y', CURRENT_DATE()) as

SELECT 
    -- String to date
    TO_DATE('01/15/2024', 'MM/dd/yyyy') as us_date,
    TO_DATE('15/01/2024', 'dd/MM/yyyy') as eu_date,
    
    -- String to timestamp
    TO_TIMESTAMP('2024-01-15 14:30:00', 'yyyy-MM-dd HH:mm:ss') as timestamp_val,
    
    -- Unix timestamp
    FROM_UNIXTIME(1705329000) as from_unix,
    
    -- Extract year
    YEAR(CURRENT_DATE()) as

SELECT 
    price,
    -- Different precision levels
    CAST(price AS INTEGER) as as_integer,  -- Truncates decimals
    CAST(price AS DECIMAL(10,0)) as as_decimal_0,
    CAST(price AS DECIMAL(10,2)) as as_decimal_2,
    CAST(price AS DECIMAL(10,4)) as as_decimal_4,
    -- Rounding with CAST
    ROUND(price, 2)::DECIMAL(10,2) as rounded_2
FROM (
    SELECT 123.456789 as price
)

SELECT 
    json_data,
    json_data:customer_id::INTEGER as customer_id,
    json_data:name::VARCHAR as name,
    json_data:purchase_amount::DECIMAL(10,2) as amount,
    TRY_CAST(json_data:is_premium::VARCHAR AS BOOLEAN) as is_premium
FROM

SELECT 
    json_data,
    CAST(JSON_VALUE(json_data, '$.customer_id') AS INT64) as customer_id,
    JSON_VALUE(json_data, '$.name') as name,
    CAST(JSON_VALUE(json_data, '$.purchase_amount') AS NUMERIC) as amount,
    SAFE_CAST(JSON_VALUE(json_data, '$.is_premium') AS BOOL) as is_premium
FROM

SELECT 
    json_data,
    CAST(get_json_object(json_data, '$.customer_id') AS INT) as customer_id,
    get_json_object(json_data, '$.name') as name,
    CAST(get_json_object(json_data, '$.purchase_amount') AS DECIMAL(10,2)) as amount,
    TRY_CAST(get_json_object(json_data, '$.is_premium') AS BOOLEAN) as is_premium
FROM

SELECT *
FROM raw_data
WHERE TRY_CAST(age_column AS INTEGER) IS NOT NULL
  AND TRY_CAST(date_column AS DATE) IS NOT NULL

SELECT 
    COALESCE(TRY_CAST(value AS INTEGER), 0) as value_with_default
FROM

SELECT 
    COUNT(*) as total_records,
    COUNT(TRY_CAST(column AS INTEGER)) as valid_conversions,
    COUNT(*) - COUNT(TRY_CAST(column AS INTEGER)) as failed_conversions
FROM