Day Of Month Must Be Between 1 And Last Day Of Month

My goal is to:

A) extract subscriber numbers from TCME153.SUB then
B) bounce those subscriber numbers off of a disconnect date i.e. DISCO_DTE_SBB then
C) bounce A) and B) off of an item table i.e. ITV_ITEM_VALUE

My hope is that the first query works as intended. Second and third queries throw error 'ORA-01847: DAY OF MONTH MUST BE BETWEEN 1 AND LAST DAY OF MONTH'.

1) SELECT DISTINCT SUB_ACCT_NO_ITV
FROM OPS$MDC.ITV_ITEM_VALUE, OPS$MDC.SBB_BASE, TCME153.SUB
WHERE EXISTS (SELECT SBB_BASE.DISCO_DTE_SBB FROM (SELECT SUB
FROM TCME153.SUB));

2) SELECT DISTINCT SUB_ACCT_NO_ITV
FROM OPS$MDC.ITV_ITEM_VALUE, OPS$MDC.SBB_BASE, TCME153.SUB

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