Error Code: 2013 Lost connection to MySQL server during query - MySQL server

[Miroljub Nikolic]

During execution of query we got Error Code: 2013 Lost connection to MySQL server. We have 3 tables OCT_15_SSBSECT_FALL2022 (3410 rows, columns: SSBSECT_TERM_CODE varchar(20)
SSBSECT_CRN varchar(20)
SSBSECT_PTRM_CODE varchar(20)
SSBSECT_SUBJ_CODE varchar(20)
SSBSECT_CRSE_NUMB varchar(20)
SSBSECT_SEQ_NUMB varchar(20)
SSBSECT_SSTS_CODE varchar(20)
SSBSECT_SCHD_CODE varchar(20)
SSBSECT_CAMP_CODE varchar(20)
SSBSECT_CRSE_TITLE varchar(30)
SSBSECT_CREDIT_HRS decimal(7,3)
SSBSECT_BILL_HRS decimal(7,3)
SSBSECT_GMOD_CODE varchar(20)
SSBSECT_SAPR_CODE varchar(20)
SSBSECT_SESS_CODE varchar(20)
SSBSECT_LINK_IDENT varchar(20)
SSBSECT_PRNT_IND varchar(20)
SSBSECT_GRADABLE_IND varchar(20)
SSBSECT_TUIW_IND varchar(20)
SSBSECT_REG_ONEUP bigint(20)
SSBSECT_PRIOR_ENRL bigint(20)
SSBSECT_PROJ_ENRL bigint(20)
SSBSECT_MAX_ENRL bigint(20)
SSBSECT_ENRL bigint(20)
SSBSECT_SEATS_AVAIL bigint(20)
SSBSECT_TOT_CREDIT_HRS decimal(9,3)
SSBSECT_CENSUS_ENRL bigint(20)
SSBSECT_CENSUS_ENRL_DATE datetime
SSBSECT_ACTIVITY_DATE datetime
SSBSECT_PTRM_START_DATE datetime
SSBSECT_PTRM_END_DATE datetime
SSBSECT_PTRM_WEEKS bigint(20)
SSBSECT_RESERVED_IND varchar(20)
SSBSECT_WAIT_CAPACITY bigint(20)
SSBSECT_WAIT_COUNT bigint(20)
SSBSECT_WAIT_AVAIL bigint(20)
SSBSECT_LEC_HR decimal(9,3)
SSBSECT_LAB_HR decimal(9,3)
SSBSECT_OTH_HR decimal(9,3)
SSBSECT_CONT_HR decimal(9,3)
SSBSECT_ACCT_CODE varchar(20)
SSBSECT_ACCL_CODE varchar(20)
SSBSECT_CENSUS_2_DATE datetime
SSBSECT_ENRL_CUT_OFF_DATE datetime
SSBSECT_ACAD_CUT_OFF_DATE datetime
SSBSECT_DROP_CUT_OFF_DATE datetime
SSBSECT_CENSUS_2_ENRL bigint(20)
SSBSECT_VOICE_AVAIL varchar(20)
SSBSECT_CAPP_PREREQ_TEST_IND varchar(20)
SSBSECT_GSCH_NAME varchar(20)
SSBSECT_TITLE varchar(30)
SSBSECT_BEST_OF_COMP bigint(20)
SSBSECT_SUBSET_OF_COMP bigint(20)
SSBSECT_INSM_CODE varchar(20)
SSBSECT_REG_FROM_DATE datetime
SSBSECT_REG_TO_DATE datetime
SSBSECT_LEARNER_REGSTART_FDATE datetime
SSBSECT_LEARNER_REGSTART_TDATE datetime
SSBSECT_DUNT_CODE varchar(20)
SSBSECT_NUMBER_OF_UNITS decimal(7,2)
SSBSECT_NUMBER_OF_EXTENSIONS bigint(20)
SSBSECT_DATA_ORIGIN varchar(30)
SSBSECT_USER_ID varchar(30)
SSBSECT_INTG_CDE varchar(20)
SSBSECT_PREREQ_CHK_METHOD_CDE varchar(20)
SSBSECT_KEYWORD_INDEX_ID varchar(30)
SSBSECT_SCORE_OPEN_DATE datetime
SSBSECT_SCORE_CUTOFF_DATE datetime
SSBSECT_REAS_SCORE_OPEN_DATE datetime
SSBSECT_REAS_SCORE_CTOF_DATE datetime
SSBSECT_SURROGATE_ID bigint(20)
SSBSECT_VERSION bigint(20)
SSBSECT_VPDI_CODE varchar(20)
SSBSECT_OVERRIDE_DUR_IND varchar(20)
SSBSECT_REFUND_CUTOFF_DATE datetime
SSBSECT_REG_AUTH_ACTIVE_CDE varchar(20)
SSBSECT_ACYR_CODE varchar(20)
SSBSECT_REFUND_CUT_OFF_DATE datetime
SSBSECT_REG_AUTH_ACTIVE_IND varchar(20)),

OCT_15_SWBENRD_FALL2022(60 000 rows, columns:
SSBSECT_TERM_CODE varchar(20)
SSBSECT_CRN varchar(20)
SSBSECT_PTRM_CODE varchar(20)
SSBSECT_SUBJ_CODE varchar(20)
SSBSECT_CRSE_NUMB varchar(20)
SSBSECT_SEQ_NUMB varchar(20)
SSBSECT_SSTS_CODE varchar(20)
SSBSECT_SCHD_CODE varchar(20)
SSBSECT_CAMP_CODE varchar(20)
SSBSECT_CRSE_TITLE varchar(30)
SSBSECT_CREDIT_HRS decimal(7,3)
SSBSECT_BILL_HRS decimal(7,3)
SSBSECT_GMOD_CODE varchar(20)
SSBSECT_SAPR_CODE varchar(20)
SSBSECT_SESS_CODE varchar(20)
SSBSECT_LINK_IDENT varchar(20)
SSBSECT_PRNT_IND varchar(20)
SSBSECT_GRADABLE_IND varchar(20)
SSBSECT_TUIW_IND varchar(20)
SSBSECT_REG_ONEUP bigint(20)
SSBSECT_PRIOR_ENRL bigint(20)
SSBSECT_PROJ_ENRL bigint(20)
SSBSECT_MAX_ENRL bigint(20)
SSBSECT_ENRL bigint(20)
SSBSECT_SEATS_AVAIL bigint(20)
SSBSECT_TOT_CREDIT_HRS decimal(9,3)
SSBSECT_CENSUS_ENRL bigint(20)
SSBSECT_CENSUS_ENRL_DATE datetime
SSBSECT_ACTIVITY_DATE datetime
SSBSECT_PTRM_START_DATE datetime
SSBSECT_PTRM_END_DATE datetime
SSBSECT_PTRM_WEEKS bigint(20)
SSBSECT_RESERVED_IND varchar(20)
SSBSECT_WAIT_CAPACITY bigint(20)
SSBSECT_WAIT_COUNT bigint(20)
SSBSECT_WAIT_AVAIL bigint(20)
SSBSECT_LEC_HR decimal(9,3)
SSBSECT_LAB_HR decimal(9,3)
SSBSECT_OTH_HR decimal(9,3)
SSBSECT_CONT_HR decimal(9,3)
SSBSECT_ACCT_CODE varchar(20)
SSBSECT_ACCL_CODE varchar(20)
SSBSECT_CENSUS_2_DATE datetime
SSBSECT_ENRL_CUT_OFF_DATE datetime
SSBSECT_ACAD_CUT_OFF_DATE datetime
SSBSECT_DROP_CUT_OFF_DATE datetime
SSBSECT_CENSUS_2_ENRL bigint(20)
SSBSECT_VOICE_AVAIL varchar(20)
SSBSECT_CAPP_PREREQ_TEST_IND varchar(20)
SSBSECT_GSCH_NAME varchar(20)
SSBSECT_TITLE varchar(30)
SSBSECT_BEST_OF_COMP bigint(20)
SSBSECT_SUBSET_OF_COMP bigint(20)
SSBSECT_INSM_CODE varchar(20)
SSBSECT_REG_FROM_DATE datetime
SSBSECT_REG_TO_DATE datetime
SSBSECT_LEARNER_REGSTART_FDATE datetime
SSBSECT_LEARNER_REGSTART_TDATE datetime
SSBSECT_DUNT_CODE varchar(20)
SSBSECT_NUMBER_OF_UNITS decimal(7,2)
SSBSECT_NUMBER_OF_EXTENSIONS bigint(20)
SSBSECT_DATA_ORIGIN varchar(30)
SSBSECT_USER_ID varchar(30)
SSBSECT_INTG_CDE varchar(20)
SSBSECT_PREREQ_CHK_METHOD_CDE varchar(20)
SSBSECT_KEYWORD_INDEX_ID varchar(30)
SSBSECT_SCORE_OPEN_DATE datetime
SSBSECT_SCORE_CUTOFF_DATE datetime
SSBSECT_REAS_SCORE_OPEN_DATE datetime
SSBSECT_REAS_SCORE_CTOF_DATE datetime
SSBSECT_SURROGATE_ID bigint(20)
SSBSECT_VERSION bigint(20)
SSBSECT_VPDI_CODE varchar(20)
SSBSECT_OVERRIDE_DUR_IND varchar(20)
SSBSECT_REFUND_CUTOFF_DATE datetime
SSBSECT_REG_AUTH_ACTIVE_CDE varchar(20)
SSBSECT_ACYR_CODE varchar(20)
SSBSECT_REFUND_CUT_OFF_DATE datetime
SSBSECT_REG_AUTH_ACTIVE_IND varchar(20))
and
OCT_15_SWBENRS_FALL2022 (7800 rows, columns: SSBSECT_TERM_CODE varchar(20)
SSBSECT_CRN varchar(20)
SSBSECT_PTRM_CODE varchar(20)
SSBSECT_SUBJ_CODE varchar(20)
SSBSECT_CRSE_NUMB varchar(20)
SSBSECT_SEQ_NUMB varchar(20)
SSBSECT_SSTS_CODE varchar(20)
SSBSECT_SCHD_CODE varchar(20)
SSBSECT_CAMP_CODE varchar(20)
SSBSECT_CRSE_TITLE varchar(30)
SSBSECT_CREDIT_HRS decimal(7,3)
SSBSECT_BILL_HRS decimal(7,3)
SSBSECT_GMOD_CODE varchar(20)
SSBSECT_SAPR_CODE varchar(20)
SSBSECT_SESS_CODE varchar(20)
SSBSECT_LINK_IDENT varchar(20)
SSBSECT_PRNT_IND varchar(20)
SSBSECT_GRADABLE_IND varchar(20)
SSBSECT_TUIW_IND varchar(20)
SSBSECT_REG_ONEUP bigint(20)
SSBSECT_PRIOR_ENRL bigint(20)
SSBSECT_PROJ_ENRL bigint(20)
SSBSECT_MAX_ENRL bigint(20)
SSBSECT_ENRL bigint(20)
SSBSECT_SEATS_AVAIL bigint(20)
SSBSECT_TOT_CREDIT_HRS decimal(9,3)
SSBSECT_CENSUS_ENRL bigint(20)
SSBSECT_CENSUS_ENRL_DATE datetime
SSBSECT_ACTIVITY_DATE datetime
SSBSECT_PTRM_START_DATE datetime
SSBSECT_PTRM_END_DATE datetime
SSBSECT_PTRM_WEEKS bigint(20)
SSBSECT_RESERVED_IND varchar(20)
SSBSECT_WAIT_CAPACITY bigint(20)
SSBSECT_WAIT_COUNT bigint(20)
SSBSECT_WAIT_AVAIL bigint(20)
SSBSECT_LEC_HR decimal(9,3)
SSBSECT_LAB_HR decimal(9,3)
SSBSECT_OTH_HR decimal(9,3)
SSBSECT_CONT_HR decimal(9,3)
SSBSECT_ACCT_CODE varchar(20)
SSBSECT_ACCL_CODE varchar(20)
SSBSECT_CENSUS_2_DATE datetime
SSBSECT_ENRL_CUT_OFF_DATE datetime
SSBSECT_ACAD_CUT_OFF_DATE datetime
SSBSECT_DROP_CUT_OFF_DATE datetime
SSBSECT_CENSUS_2_ENRL bigint(20)
SSBSECT_VOICE_AVAIL varchar(20)
SSBSECT_CAPP_PREREQ_TEST_IND varchar(20)
SSBSECT_GSCH_NAME varchar(20)
SSBSECT_TITLE varchar(30)
SSBSECT_BEST_OF_COMP bigint(20)
SSBSECT_SUBSET_OF_COMP bigint(20)
SSBSECT_INSM_CODE varchar(20)
SSBSECT_REG_FROM_DATE datetime
SSBSECT_REG_TO_DATE datetime
SSBSECT_LEARNER_REGSTART_FDATE datetime
SSBSECT_LEARNER_REGSTART_TDATE datetime
SSBSECT_DUNT_CODE varchar(20)
SSBSECT_NUMBER_OF_UNITS decimal(7,2)
SSBSECT_NUMBER_OF_EXTENSIONS bigint(20)
SSBSECT_DATA_ORIGIN varchar(30)
SSBSECT_USER_ID varchar(30)
SSBSECT_INTG_CDE varchar(20)
SSBSECT_PREREQ_CHK_METHOD_CDE varchar(20)
SSBSECT_KEYWORD_INDEX_ID varchar(30)
SSBSECT_SCORE_OPEN_DATE datetime
SSBSECT_SCORE_CUTOFF_DATE datetime
SSBSECT_REAS_SCORE_OPEN_DATE datetime
SSBSECT_REAS_SCORE_CTOF_DATE datetime
SSBSECT_SURROGATE_ID bigint(20)
SSBSECT_VERSION bigint(20)
SSBSECT_VPDI_CODE varchar(20)
SSBSECT_OVERRIDE_DUR_IND varchar(20)
SSBSECT_REFUND_CUTOFF_DATE datetime
SSBSECT_REG_AUTH_ACTIVE_CDE varchar(20)
SSBSECT_ACYR_CODE varchar(20)
SSBSECT_REFUND_CUT_OFF_DATE datetime
SSBSECT_REG_AUTH_ACTIVE_IND varchar(20)).
If we have 60 000 rows in each table, everything is working.
Query that we try is:

Select a.PIDM_KEY, a.TERM_CODE_KEY, a.LEVL_CODE, a.COlL_CODE, a.COlL_DESC, a.PROGRAM_1, a.MAJR_CODE1, a.MAJR_DESC1, a.TOTAL_CREDIT_HOURS, c.SSBSECT_SCHD_CODE,
CASE
WHEN (a.LEVL_CODE = 'UG' AND a.TOTAL_CREDIT_HOURS< 12) THEN ROUND(a.TOTAL_CREDIT_HOURS/150,1)
WHEN (a.LEVL_CODE in ('GR','CP') AND a.TOTAL_CREDIT_HOURS< 12 AND a.PROGRAM_1 LIKE 'MPH%' and c.SSBSECT_SCHD_CODE not in ('X','Y','Z','O','T','P')) THEN round(a.TOTAL_CREDIT_HOURS/120,1)
WHEN (a.LEVL_CODE in ('GR','CP') AND a.TOTAL_CREDIT_HOURS< 9 AND a.PROGRAM_1 NOT LIKE 'MPH%' and c.SSBSECT_SCHD_CODE not in ('T','H','M','MD','O','DP')) THEN round(a.TOTAL_CREDIT_HOURS/90,1)
ELSE 1
END AS FTE_STUDENTS,
CASE
WHEN (a.LEVL_CODE = 'UG' AND a.TOTAL_CREDIT_HOURS>= 12) THEN '1'
WHEN (a.LEVL_CODE in ('PH','PR')) THEN '1'
WHEN (a.LEVL_CODE in ('GR','CP') AND c.SSBSECT_SCHD_CODE in ('T','H','M','MD','O','DP')) THEN '1'
WHEN (a.LEVL_CODE in ('GR','CP') AND a.TOTAL_CREDIT_HOURS>= 12 AND a.PROGRAM_1 LIKE 'MPH%' and c.SSBSECT_SCHD_CODE not in ('X','Y','Z','O','T','P')) THEN '1'
WHEN (a.LEVL_CODE in ('GR','CP') AND a.TOTAL_CREDIT_HOURS>= 9 AND a.PROGRAM_1 NOT LIKE 'MPH%' and c.SSBSECT_SCHD_CODE not in ('T','H','M','MD','O','DP')) THEN '1'
ELSE '0'
END AS Full_Time
from Oct_15_SWBENRS_Fall2022 a, Oct_15_SWBENRD_Fall2022 b, Oct_15_SSBSECT_Fall2022 c
where a.TERM_CODE_KEY = b.TERM_CODE_KEY and b.TERM_CODE_KEY = c.SSBSECT_TERM_CODE
and a.TERM_CODE_KEY in ('202310')
and a.PIDM_KEY = b.PIDM_KEY
and b.CRN_KEY = c.SSBSECT_CRN
and a.ESTS_CODE = 'EL' and a.REGISTERED_IND = 'Y' and a.ENROLLMENT_AR_IND IN('Y','C')
and a.MAJR_CODE1 in ('APPM')
GROUP BY a.PIDM_KEY, a.TERM_CODE_KEY, a.LEVL_CODE, a.COlL_CODE, a.COlL_DESC, a.PROGRAM_1, a.MAJR_CODE1, a.MAJR_DESC1, a.TOTAL_CREDIT_HOURS, c.SSBSECT_SCHD_CODE
order by 1,2,3,4;