Schema:
CREATE TABLE d_icd_procedures (
    row_id number,
    icd9_code text,
    short_title text,
    long_title text
)

CREATE TABLE d_items (
    row_id number,
    itemid number,
    label text,
    linksto text
)

CREATE TABLE inputevents_cv (
    row_id number,
    subject_id number,
    hadm_id number,
    icustay_id number,
    charttime time,
    itemid number,
    amount number
)

CREATE TABLE labevents (
    row_id number,
    subject_id number,
    hadm_id number,
    itemid number,
    charttime time,
    valuenum number,
    valueuom text
)

CREATE TABLE chartevents (
    row_id number,
    subject_id number,
    hadm_id number,
    icustay_id number,
    itemid number,
    charttime time,
    valuenum number,
    valueuom text
)

CREATE TABLE transfers (
    row_id number,
    subject_id number,
    hadm_id number,
    icustay_id number,
    eventtype text,
    careunit text,
    wardid number,
    intime time,
    outtime time
)

CREATE TABLE diagnoses_icd (
    row_id number,
    subject_id number,
    hadm_id number,
    icd9_code text,
    charttime time
)

CREATE TABLE prescriptions (
    row_id number,
    subject_id number,
    hadm_id number,
    startdate time,
    enddate time,
    drug text,
    dose_val_rx text,
    dose_unit_rx text,
    route text
)

CREATE TABLE cost (
    row_id number,
    subject_id number,
    hadm_id number,
    event_type text,
    event_id number,
    chargetime time,
    cost number
)

CREATE TABLE patients (
    row_id number,
    subject_id number,
    gender text,
    dob time,
    dod time
)

CREATE TABLE procedures_icd (
    row_id number,
    subject_id number,
    hadm_id number,
    icd9_code text,
    charttime time
)

CREATE TABLE outputevents (
    row_id number,
    subject_id number,
    hadm_id number,
    icustay_id number,
    charttime time,
    itemid number,
    value number
)

CREATE TABLE d_icd_diagnoses (
    row_id number,
    icd9_code text,
    short_title text,
    long_title text
)

CREATE TABLE d_labitems (
    row_id number,
    itemid number,
    label text
)

CREATE TABLE microbiologyevents (
    row_id number,
    subject_id number,
    hadm_id number,
    charttime time,
    spec_type_desc text,
    org_name text
)

CREATE TABLE icustays (
    row_id number,
    subject_id number,
    hadm_id number,
    icustay_id number,
    first_careunit text,
    last_careunit text,
    first_wardid number,
    last_wardid number,
    intime time,
    outtime time
)

CREATE TABLE admissions (
    row_id number,
    subject_id number,
    hadm_id number,
    admittime time,
    dischtime time,
    admission_type text,
    admission_location text,
    discharge_location text,
    insurance text,
    language text,
    marital_status text,
    ethnicity text,
    age number
)

Question: what are the four most frequently ordered lab tests for patients who had previously received ven cath renal dialysis within the same month, in 2104?

SQL:
SELECT d_labitems.label FROM d_labitems WHERE d_labitems.itemid IN (SELECT t3.itemid FROM (SELECT t2.itemid, DENSE_RANK() OVER (ORDER BY COUNT(*) DESC) AS c1 FROM (SELECT admissions.subject_id, procedures_icd.charttime FROM procedures_icd JOIN admissions ON procedures_icd.hadm_id = admissions.hadm_id WHERE procedures_icd.icd9_code = (SELECT d_icd_procedures.icd9_code FROM d_icd_procedures WHERE d_icd_procedures.short_title = 'ven cath renal dialysis') AND STRFTIME('%y', procedures_icd.charttime) = '2104') AS t1 JOIN (SELECT admissions.subject_id, labevents.itemid, labevents.charttime FROM labevents JOIN admissions ON labevents.hadm_id = admissions.hadm_id WHERE STRFTIME('%y', labevents.charttime) = '2104') AS t2 ON t1.subject_id = t2.subject_id WHERE t1.charttime < t2.charttime AND DATETIME(t1.charttime, 'start of month') = DATETIME(t2.charttime, 'start of month') GROUP BY t2.itemid) AS t3 WHERE t3.c1 <= 4)